Parts of South Australia have reached 45 degrees as Australia's most significant heatwave in more than five years leaves many parts of the country sweltering.

An extremely hot air mass will spread across the country tomorrow and on Friday, causing temperatures to soar into the high 40s in some states, in what could be the most severe burst of heat since the 2019-20 black summer.

Adelaide hit a top of 43 degrees today, making it the city's hottest day since February last year, with temperatures quickly climbing to 40 degrees before 10am.

READ MORE: Residents urged to leave as 1000-hectare bushfire burns through state park in Victoria's north

Firefighters had a close call after a train sparked a grass fire.

Searing temperatures and strong winds in Victoria also put firefighters on high alert with multiple blazes in the state.

An emergency bushfire warning was issued for a blaze on the Hume Freeway in Longwood East north of Melbourne this afternoon.

Authorities believe the worst may not be over yet.

"Friday is one of those days that we've not seen for some time," Emergency Management Victoria Commissioner Tim Wiebusch said.

"We will have the whole state at a very high risk of extreme fire danger."

Country Fire Authority (CFA) Chief Officer Jason Heffernan said fires under the current weather conditions were "uncontrollable".

"If a fire starts and takes hold, it will spread very quickly," Heffernan said.

READ MORE: 'Doesn't feel fair': Australian-British citizens caught out by new passport rule

Melbourne recorded a top of 41 degrees today, beating the previous monthly record of 40 degrees which was set in January 2020.

Residents in many parts of the state are under a total fire ban including the Melbourne and Geelong areas, as well as Wimmera, south-west and central parts of the state.

The ban means no fires are allowed to remain alight in the open air from now until midnight.

Heffernan urged residents to be prepared.

"It is really important people take the actions needed to protect themselves and their family, and that preparedness starts early," Heffernan said.

"Understand how the increased fire risk will impact you and ensure your fire plan covers all possible contingencies.

"Download the VicEmergency App to stay well informed."

The scorching heat has been building this week and is forecast to smother multiple states into the weekend, according to weather data firm Weatherzone.

Extreme heat will be widespread in South Australia for the rest of the week, with the three days from today to Friday expected to see maximum temperatures exceeding 46 degrees over the state's inland.

READ MORE: Bondi terror attack victim Peter Meagher's brother sends out poignant message at funeral

The highest temperatures are likely to occur in the state's north-east pastoral district and eastern inland over the next three days.

The sweltering heat has forced the closure of popular South Australian zoo Monarto Safari Park, 16 kilometres west of the Murray River.

Most of NSW and the Australian Capital Territory will be hot from today until Saturday, before the heat retreats to northern NSW on Sunday.

The highest temperatures of the week will likely be in the south-west, where Balranald and Wentworth are forecast to hit 46 degrees on Thursday and Friday, according to Weatherzone.

Perth and other areas in the southwest of WA are escaping this week's heat, with maximums hovering around the high 20s and low 30s for most of the week.

Deputy Coordinator-General of the National Emergency Management Agency Katarina Carroll said the heatwave conditions will last until the weekend.

She told Today this morning that more people die from heat-related conditions than any other natural disaster.

"You have to prepare for those four days," Carroll said.

"So stay hydrated… wherever you can, keep cool as much as you can and look after the vulnerable.

"That is incredibly important the children, the elderly and listen to local emergency services."

Meanwhile residents living along the North Queensland coast are being urged to prepare as a tropical low forms off-shore.

The weather system is expected to bring very heavy rainfall to the region by tomorrow, with totals expected to exceed 300 millimetres in the coming days.

Sign up here to receive our daily newsletters and breaking news alerts, sent straight to your inbox.

Police say the driver became suspicious of a man he gave a lift to and rang officers.

The Melbourne sinkhole that opened up near a major tunnelling project poses "serious questions", an expert says.

The collapsed turf was seen at AJ Burkitt Oval in Heidelberg on Monday afternoon, drawing a crowd of onlookers.

Victorian Infrastructure Delivery Authority (VIDA) chief executive Duncan Elliott said yesterday two tunnel boring machines digging underground as part of the North East Link were located metres from the site.

READ MORE: Teenager stabbed at house party left fighting for life

Engineer and former president of the International Tunnelling and Underground Space Association Arnold Dix told Today he would bet that the project and the sinkhole were linked.

"A sinkhole on the surface also means that there's possibility of difficulties underground, so we've got to think of our people underground and their safety and of course, the safety of people up on the surface," he said.

"So something's gone wrong.

"And some serious questions have to be answered about how it's gone wrong, why it's gone wrong, to make sure it doesn't happen again."

READ MORE: Less than 1 per cent of Jeffrey Epstein files released

He said that such a sinkhole posed a "serious risk", noting that the oval appeared to have been recently mowed.

"If I was mowing that oval and it had collapsed and I went in, that's really serious risk," he said.

"You could be you could be seriously injured or killed if you fell into it."

But he said the oval would be safe to use again once the issue had been identified and corrected.

"It could be a change in the movement or the ground level of water underneath," he said.

"It could be that they've had more material go into their tunnel boring machine than they were expecting. There's a whole range of reasons for it."

READ MORE: 'A lot of people were killed': Trump boasts about Maduro operation

However, he said, the fact that the sinkhole had not yet expanded – though he noted that was a possibility – and the fact that nobody had yet been injured, meant it was the sinkhole he'd like to see in his backyard, if he had to have one.

"This is the cute and cuddly sort, this one," he said.

"Let's keep it that way."

A North East Link spokesperson yesterday told 9news.com.au they were aware of the sinkhole "in the vicinity" of the tunnelling operation.

"The area has been secured and crews are closely monitoring the site and surrounding areas – and we strongly advise people to avoid the area while investigations into the cause are underway," they said.

"No injuries have been reported and there is no immediate threat to the community or residential properties."

DOWNLOAD THE 9NEWS APP: Stay across all the latest in breaking news, sport, politics and the weather via our news app and get notifications sent straight to your smartphone. Available on the Apple App Store and Google Play.

A French man wanted for the alleged sexual assault of a woman after she had fallen at a nightclub on New Year's Day has faced court.

Adam Berguiga, 22, appeared in custody at Melbourne Magistrates Court on Wednesday charged with seven offences, including rape and recklessly causing injury.

He was arrested in Sydney after police had been searching for him and put a warrant out for his arrest.

READ MORE: Socialite Brynne Edelsten charged with drug trafficking

Police say Berguiga helped a woman from the dance floor after she fell while celebrating New Year's Eve with friends at a Melbourne nightclub.

It is alleged he then sexually assaulted the woman shortly after, about 4.30am on January 1, on Corrs Lane, a laneway in Melbourne's CBD.

Berguiga is accused of leading the victim to Little Bourke Street before leaving the area, police claim.

He was arrested at Sydney Airport about 12pm on January 4 and extradited to Melbourne.

Among his charges are two counts of rape, intentionally sexually touching without consent, assault and recklessly causing injury to bruise shoulder, causing soreness to head and grazes to knees, court documents reveal.

He is further accused of driving on Russell Street and King Street in Melbourne's CBD on January 1 without a licence.

READ MORE: Alleged international car theft syndicate targeted Toyota LandCruisers and Prados in Brisbane

Berguiga, who was assisted by a French interpreter, does not speak any English and was vulnerable in custody due to his young age, his lawyer told the court.

She said it was his first time in custody and asked for her client to be seen by a mental health nurse.

He had one supporter in court, who waved at him and the magistrate during the brief hearing.

Berguiga did not apply for bail and will return to court for a committal mention on April 10.

Help is available from the Men's Referral Service on 1300 766 491.

National Sexual Assault, Domestic Family Violence Counselling Service 1800RESPECT (1800 737 732).

Five batches of Nestle baby formula have been recalled across Australia as part of a global move due to a potentially dangerous toxin that can cause digestive issues.

Nestle's Alfamino formula for babies with milk allergies is sold at pharmacies, hospitals and available online nationwide.

The recall only applies to the products with the following date and batch number details.

• Use by date 17.04.2027, Batch number 51070017Y2
• Use by date 18.04.2027, Batch number 51080017Y1
• Use by date 28.05.2027, Batch number 51480017Y3
• Use by date 29.05.2027, Batch number 51490017Y1
• Use by date 22.07.2027, Batch number 52030017Y1

Consumers are being urged to return the product to the place of purchase for a full refund.

Any consumers concerned about the health of their babies should seek medical advice.

There have been no reports of sickness in Australia related to the recall so far.

DOWNLOAD THE 9NEWS APP: Stay across all the latest in breaking news, sport, politics and the weather via our news app and get notifications sent straight to your smartphone. Available on the Apple App Store and Google Play.

A woman was found dead on Jan 1; a man was found the next day elsewhere on the property.

One motorist was recently stopped after driving at more than twice the speed limit.

Australians are part of the growing number of people worldwide who have been targeted on Elon Musk's AI chatbot Grok, which allowed sexualised images of women and children to be generated without their consent.

Grok Imagine, an AI image generator that allows users to create photos and videos with text prompts, was first launched in July but started causing issues after it was opened to the public in October.

The tool, which is hosted on X, has been allowing users to nudify images of or sexually depict others as recently as today.

READ MORE: ATO vow to ban tax dodgers from leaving Australia

Grok differs from other AI generative platforms as the images are publicly shared and can be easily spread.

Since late last year, the eSafety Commission has received several reports of Grok being used to generate unconsensual sexualised images.

"Some reports relate to images of adults, which are assessed under our Image-Based Abuse scheme, while others relate to potential child sexual exploitation material, which are assessed under our Illegal and Restricted Content scheme," a spokesperson said.

The reports of adults are currently being assessed, while reports of children did not meet the threshold for child sexual exploitation material.

eSafety has not taken any action, but said it was worried about the use of generative AI.

"eSafety remains concerned about the increasing use of generative AI to sexualise or exploit people, particularly where children are involved," the spokesperson said.

READ MORE: AI dominates as Australia's fastest-growing jobs revealed

Analysis from non-profit outfit AI Forensics said in a report that it analysed 20,000 images generated by Grok between December 25 and January 1 and found that two per cent depicted a person who appeared to be 18 or younger, including 30 of young or very young women or girls, in bikinis or transparent clothes.

One of the victims includes Musk's former partner, Ashley St Clair, who became estranged from the tech billionaire after the birth of their child in 2024.

She told The Guardian users have used Grok to create "revenge porn".

"I felt horrified, I felt violated, especially seeing my toddler's backpack in the back of it," she told the publication. 

X did not deny that unconsensual sexualised content exists on Grok, but warned that users could be suspended or referred to law enforcement.

"We take action against illegal content on X, including Child Sexual Abuse Material, by removing it, permanently suspending accounts, and working with local governments and law enforcement as necessary," X said through its Safety account.

"Anyone using or prompting Grok to make illegal content will suffer the same consequences as if they upload illegal content."

READ MORE: Aussies among tourists trapped on remote desert island

https://x.com/Safety/status/2007648212421587223

But governments and regulators around the world called for Musk's platform to do more to combat abusive content. 

The United Kingdom's Technology Secretary Liz Kendall said the content is "absolutely appalling, and unacceptable in decent society".

"We cannot and will not allow the proliferation of these demeaning and degrading images, which are disproportionately aimed at women and girls," she said.

The country's communications regulator Ofcom said it made "urgent contact" with X.

The European Union said it was aware of the content and strongly condemned Grok.

"This is not spicy. This is illegal. This is appalling. This is disgusting. This is how we see it, and this has no place in Europe. This is not the first time that Grok is generating such output," European Commission spokesman Thomas Regnier said.

France, Poland, India, Malaysia and Brazil also called for Musk to implement strict rules and take action.

– With Associated Press

DOWNLOAD THE 9NEWS APP: Stay across all the latest in breaking news, sport, politics and the weather via our news app and get notifications sent straight to your smartphone. Available on the Apple App Store and Google Play.

The brother of Bondi terror attack victim Peter Meagher has used his eulogy to deliver a poignant message to the NSW Premier Chris Minns and Prime Minister Anthony Albanese on gun reform.

The 61-year-old was a highly decorated police detective as well as a loving family man and pillar of the Randwick rugby club.

"Every text message, WhatsApp and voicemail from Peter begins with 'hi darling' and ends with 'I love you'," his wife Virginia said at his funeral today.

READ MORE: Six people rushed to hospital after crash between truck and multiple cars

Meagher was working as a freelance photographer capturing Hanukkah celebrations at Bondi before the terrorists opened fire.

NSW Police Assistant Commissioner Michael Fitzgerald said he was a man who "believed in justice, and believed in good".

Today, during his funeral service in St Mary's Cathedral, Peter's brother, David, used his eulogy to send a strong message about gun reform.

"Gun reform alone will not solve hatred or extremism, but an antisemite without a gun is just a hate-filled person," he said.

"An antisemite with a gun is a killer.

READ MORE: ATO vow to ban tax dodgers from leaving Australia

"The killer on December 14 had six legally acquired high-powered guns.

"Under new laws, he would have been allowed to have four guns. What can you do with six guns that you can't do with four?"

Meagher referenced the rushed reforms through state parliament in the wake of the attack that claimed 15 innocent lives before asking friends to remember his brother for the life he lived rather than his death. 

"But if you do think about how his life ended, perhaps reflect on what can be done to prevent it from happening to someone else."

The call to lawmakers was made shortly before Peter's coffin was saluted by the federal and NSW police commissioners, and blessed by the prime minister and premier.

DOWNLOAD THE 9NEWS APP: Stay across all the latest in breaking news, sport, politics and the weather via our news app and get notifications sent straight to your smartphone. Available on the Apple App Store and Google Play.

The batches are part of a wider international recall by the Swiss food giant.