A "dome of heat" set to loom over south-eastern parts of Australia over the next week has fire authorities on alert, as Victorian bushfires that started almost two weeks ago continue to burn.

A sweltering trough travelling from Western Australia is expected to hit Adelaide and Melbourne on Saturday, where the mercury is set to surge to 42 and 40 degrees respectively.

Authorities in Victoria are warning the mercury could remain above 40 degrees in northern parts of the state for up to a week.

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"Currently a dome of heat is expected to sit over Victoria, not just this weekend, but persisting well into next week," Bureau of Meteorology's Kevin Parkyn said.

Mildura is forecast to hit 43 degrees on Saturday, with an extreme fire danger rating for the Wimmera and South West Districts.

A cool south-westerly wind change will bring a reprieve for the south-west of the state, including Melbourne, on Saturday evening, but the heat is expected to stick around in northern parts.

The mercury will be somewhat cooler on the south-west coast on Sunday and Monday, before potentially record-breaking heat returns to the state on Tuesday.

Melbourne is tipped to reach 41 degrees on Tuesday as the trough travels further east, with a top of 43 possible in the suburbs.

The heat will be even more intense up north, with 47 degrees forecast for Mildura, 45 degrees in Bendigo and potentially 48 degrees in Ouyen.

"Many centres are probably going to break their all-time maximum records," Parkyn said.

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Another cool change should begin to bring relief to south-west Victoria by Tuesday afternoon.

Authorities are urging Victorians to be aware of their environment over the long-weekend and to limit the use of campfires.

"We do want people out there in Victoria spending money in regional Victoria, enjoying themselves, but we've got a lot of really severe and dangerous weather ahead of us and we just ask that people take care and act responsibly," Fire Forest Management Victoria Chief Fire Officer Chris Hardman said.

"If you are camping, with the temperatures we're seeing coming our way, do you really need a campfire at all?"

South Australians are also set to swelter through the heatwave across the week.

The mercury is expected to peak at 42 degrees in Adelaide on Saturday, before dipping slightly to 36 on Sunday and again rising to 43 degrees on Monday.

'Risk of fire will return'

Fire authorities are warning the heatwave is expected to agitate bushfires still raging across Victoria.

The Wimmera and South West districts will be under an extreme fire danger rating on Saturday, while most other parts of the state will have a high rating.

Hot, dry conditions will persist overnight on Sautrday and could exacerbate fire danger, the Bureau of Meteorology warned.

Blazes in Walwa, Wonnangatta and Mallacoota remain uncontrolled and four others are also still burning.

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More than 1500 structures have now been declared damaged or destroyed by fire and a state of disaster remains in place across Victoria.

The largest and most destructive blaze at Longwood was marked as contained at 5pm last night, meaning the fire continues to burn, but its spread has stopped.

The Longwood fire has burned through 144,000 hectares and destroyed 320 homes, with dozens more damaged and nearly 900 outbuildings impacted.

While wind speeds over the week aren't expected to be as high as the strong gusts on January 9, authorities are asking Victorians to remain vigilant.

"The risk of fire will return," CFA chief officer Jason Heffernan warned.

"We will be declaring total fire bans throughout the course of this fire event."

Parkyn warned a dry outlook could make it even more difficult to quash the fires, and any new ones that start.

"We're not expecting any significant rainfall to affect Victoria over the next two weeks," he said.

Almost two dozen firefighters have been called in from New Zealand to help bolster efforts.

They will be joined by 74 Canadian firefighters expected to arrive in Victoria early next week.

The ‘shaken’ victim was left with serious injuries after the attack.

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Day-time highs in Auckland and Northland drop from 25C to about 19C or 20C.

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People are unaccounted for after a landslide crumbled on to a Mount Maunganui campground.

Around 30 whānau evacuated to centres and marae across Tairāwhiti overnight.

Young people are among those still unaccounted for at the campground.

Less than a year into her reign, the federal Liberal Party's first-ever female leader is sitting on death row.

For the second time in mere months, Opposition Leader Sussan Ley is commanding only a tattered, single-party Coalition.

After announcing his party's split from the "untenable" alliance, Nationals leader David Littleproud left some blunt criticism as a parting gift for his Liberal counterpart.

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"She was aware of the consequences if she (accepted the resignations of three senators), that the National Party were being forced into an untenable position," he said.

"She still made that decision."

Littleproud and his senators who voted against the government's hate speech legislation also knew the consequences – cabinet solidarity is a fundamental principle within the Coalition agreement.

But you won't hear that retort coming from Ley anytime soon, as the opposition leader opts to avoid speaking on the national day of mourning for the Bondi terror attack.

"That is honourable and noble and in the right spirit of a day of mourning," 9News political editor Charles Croucher said. 

"But it's also leaving a lot of airtime to be filled by others, and they will be those who are against her.

"That could be the final death knell for her in that leadership position."

Ley's stint as Liberal leader began with a similar schism, but that was repaired in relatively quick time.

This one appears far less salvageable – the only cure that could bring the two parties back together is Ley's removal.

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"We cannot be part of a shadow ministry under Sussan Ley," Littleproud said.

It leaves the Liberal Party with two options: find a new leader, or continue as the opposition on its own, with fewer than 40 lower house MPs to counter the government's 94.

"It is a mess. That is the only word for it," Croucher said.

"It's a mess that's going claim at least one scalp at some point in the coming weeks, because clearly David Littleproud and Sussan Ley can't work together."

It's those numbers in parliament that made Ley's decision to accept the resignations of the three Nationals senators who broke shadow cabinet solidarity so risky.

"You're flexing muscles you don't have," Croucher said.

"There is no room to be this boisterous and stand up to the Nationals, because this is the consequence: the Coalition is split, the opposition looks feeble, and the government's getting a free ride to start 2026."

READ MORE: 'We share their grief': Australia marks day of mourning for Bondi terror attack

Making matters worse for the now-extinct Coalition is the fact this asteroid was entirely self-inflicted.

The opposition insisted parliament be urgently recalled to pass legislation following the Bondi shooting, only to rupture over the lack of time they had to examine those laws.

"The Coalition demanded parliament comes back – parliament comes back," Croucher said

"The Coalition demands that parliament splits the bill – the government splits the bill. 

"And still, they've split Coalition on this… 

"It's a remarkable self-inflicted wound, but it's coming from a party that's been inflicting wounds on itself now for the better part of four years, and it will just continue in the four weeks ahead."

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Friends say they helped plan her funeral and the future care of her two children.