Less than a day after La Niña was officially declared over by the Bureau of Meteorology (BoM), fresh warnings have been issued over a sizzling heatwave set to sweep the country's east.

Temperatures will heat up today and linger above the 30 degree mark for the remainder of the week in New South Wales, which has been flagged as being "in the bullseye of the weather system", and in parts of Queensland's southeast.

The unusually long-lasting hot burst is set to see conditions swelter to almost 40 degrees in some parts of NSW over the coming five days, with Thursday and Sunday tipped to be the most uncomfortable.

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The announcement has left firefighters on edge after a treacherous string of almost 300 bushfires lashed the state last week.

During last week's heatwave, some 19,000 hectares of land were burnt in NSW's Central West and hundreds of homes were in the firing line.

Today in Sydney's metro temperatures will reach 27 degrees before heating up to 33 tomorrow and 32 degrees on Sunday.

In the city's west, it'll reach 31 degrees today, 37 degrees tomorrow and 38 degrees on Sunday.

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Yesterday, the bureau said that the third consecutive La Niña has officially ended, but immediately issued an El Niño watch, saying there is a 50 per cent chance the latter weather phenomenon will occur later this year."

"The El Niño–Southern Oscillation (ENSO) is now neutral (neither La Niña nor El Niño) with oceanic and atmospheric indicators having returned to neutral ENSO levels," the bureau said.

"International climate models suggest neutral ENSO conditions are likely to persist through the southern autumn.

"However, there are some signs that El Niño could form later in the year.

Elsewhere around the country, it'll be cloudy and 31 degrees with a chance of showers in Brisbane, 30 and rainy at the Gold Coast, 28 and mostly fine in Canberra, 25 degrees and sunny in Melbourne, 28 degrees and partly cloudy in Adelaide and sunny a 28 degree day in Perth.

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The first koala vaccinated against chlamydia has given birth to a joey, bringing hope that the protected animals will help re-populate the vulnerable population.

The vaccine has given hope to zoologists at Currumbin Wildlife Hospital in Queensland as chlamydia in koalas can lead to blindness, infections and infertility, causing further deaths in the already declining species.

The Currumbin Wildlife Hospital is the home of Anne Chovee, the first koala to get the vaccine, and her new joey.

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"We had the two-year mark, which is very exciting, most excitingly because she's got a joey in her pouch now," research supervisor Lewis McKillop said.

"To get the vaccine registered so that any vet who's treating koalas can get it and start to use it would be a major step forward.

"Ultimately what we're trying to achieve is more breeding."

More than 250 koalas will benefit from the chlamydia vaccine, with hopes the jab will increase koala populations.

Koalas were listed as endangered in Queensland, NSW and the Australian Capital Territory in February 2022.

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There are fewer than than 57,920 koalas left in the wild.

There is a possibility that the number of koalas left in the wild has declined to 32,065, according to the Australian Koala Foundation.

Australian researchers say their study of a disease which causes chronic pain and affects one in nine women has revealed new clues about what puts women at higher risk of developing it.

Endometriosis causes chronic pain, infertility and fatigue from lesions growing outside the uterus.

University of Queensland researchers played a part in the largest ever genetic study into the condition.

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They worked with Oxford University in the UK and dozens more teams around the world to discover 42 genetic factors associated with a higher risk of the disease.

Laura Terry explained how it feels to have endometriosis.

"I don't want to walk move eat sometimes it can make you nauseous," she said.

"It can actually knock you down you can have all these sharp spasms that radiate throughout your body."

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Dr Sally Mortlock from UQ's Institute for Molecular Bioscience said they looked at differences in the DNA code in tens of thousands of women.

"We combined data from 60,000 women with endo and 700,000 women without endometriosis," Mortlock said.

"Very little is known about the causes of endometriosis, but studying genetics can give us clues to the biological processes that are the basis for onset and progression.

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"Before this study there were 17 genetic regions associated with endometriosis and now we have 42 regions with much richer data.

"It means we can find out what genes in these regions do and find new drug targets, leading to new treatments."

Until now endometriosis has taken up to ten years to diagnose, but these findings promise to help speed up that process, and improve the quality of life for sufferers plus open new avenues for treatment.

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Profesor Grant Montgomery from UQ's Institute for Molecular Bioscience has been studying the genetics of endometriosis for more than 20 years and said the study was an important step towards improved treatment and diagnosis.

"One of the difficulties with the delay of course is that the disease progresses at least for some women and so by the time they get to treatment you know the disease might be more severe," he said.

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TV star Bindi Irwin recently revealed her long battle with the condition.

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Three people are in a moderate condition, initial reports suggest.

The 2.75m great white Daisy has shown up again after going missing for a month.

A young mother who was killed alongside her two-year-old son in a crash in Sydney's south-west has been identified while her four-month-old baby fights for life in hospital.

Katherine Prahastono was driving on the Hume Motorway at Menangle Park when she attempted a U-turn and collided with a cement truck yesterday morning. 

Both Prahastono and her son died at the scene while her baby was taken to Westmead Children's Hospital, where he remains in a critical condition.

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"Paramedics and two specialist medical teams worked alongside Fire and Rescue NSW to free the child who was then intubated on-scene before being airlifted," NSW Ambulance Chief Superintendent Mark Gibbs said.

Gibbs said it was a miracle the baby survived the horror incident.

"I think it is hard to believe that anybody did survive that wreckage (from) such a tragic and high-speed incident," he said.

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The truck driver was not injured and has been taken for mandatory testing.

Police are investigating the cause of the crash and will prepare a report for the Coroner.

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Artists and creators still battle to get their ideas funded in New Zealand.

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