Authorities are evacuating people from areas in central and western Victoria as dangerous fire conditions grip several states across the south-east.

Damaging winds will fan extreme fire danger on Thursday as hot and dry weather envelops large parts of Victoria, south-west New South Wales and much of eastern South Australia.

At 9am AEDT, there were fires burning in Victoria, including Grampians national park, Bullengarook, Creswick and at the Gurdies. Authorities expecting those fires to grow on Thursday.

Victoria State Control Centre spokesperson Luke Hegarty urged residents on those areas to leave the area by 10am to protect themselves and their families.

“You need to leave those areas. Move to somewhere else, somewhere safe. That is the way to protect yourself and your family.”

He said all residents in Victoria should be checking their fire plan, and to be prepared if a fire starts nearby.

“Know what you’re going to do if a fire starts. And if you’re planning on traveling today, reconsider your need to travel. This is not a day to be outside. This is not a day to be undertaking any sort of travel unless absolutely necessary.”

Victoria is preparing to face the most dangerous fire conditions since the 2019–20 Black Summer. Gusty winds were expected for much of the day, as well as on Friday and Saturday, exacerbating fire dangers across the state.

Temperatures were set to reach the high 30s and into the 40s for much of Victoria and inland Australia, with the central western Queensland town of Birdsville forecast to hit 47C.

Victorian premier, Jacinta Allan, took to X with a blunt message:

“The message couldn’t be clearer: today’s a day of total fire ban across Victoria. Don’t be a dickhead. No fires to be lit.”

Thursday’s conditions were expected to be “the worst since the 2019-20 Black Summer bushfire season”, Allan said.

Gusts of up to 100km/h are strong enough to bring down trees and power lines and cause minor power outages, the Bureau of Meteorology senior forecaster Dean Narramore said.

A high-pressure trough which brought temperatures in the high 30s to South Australia on Christmas Day is slowly trekking across the border to Victoria.

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All but one region of Victoria are set to face extreme fire risk on Thursday.

Total fire bans have also been declared for South Australia’s Mid North, Riverland, Murraylands, Upper South East and Lower South East regions.

The dangerous conditions could further fuel an out-of-control bushfire in Victoria’s Grampians national park which has been burning for days, covering more than 40,000 hectares.

Residents in the Grampians towns of Bornes Hill, Moyston and Pomonal were also ordered to leave on Wednesday as the blaze raced towards them.

Narramore said the combination of strong winds, high temperatures and dry air made for dangerous fire activity.

“Any fire that does get going or already is ongoing around the Grampians will likely be uncontrollable and uncontainable, leading to dangerous and erratic fire behaviour,” he said.

Firefighters from multiple states have deployed to help their Victorian counterparts as crews work to secure containment lines on Boxing Day.

Power provider AusNet warned customers that power cuts could be triggered to prevent bushfires from starting and outages could last longer to ensure safety.

As a cool change washes over Victoria on Thursday night, hot, dry and windy conditions will push into parts of central north-eastern NSW, bringing extreme fire danger on Friday.

The bureau was forecasting hot to very hot temperatures throughout South Australia, with possible thunderstorms ahead of a cool change.

In South Australia, a grass and stubble fire at Para Hills, a northern suburb of Adelaide, that started on Christmas afternoon, was yet to be contained.

The Country Fire Service (CFS) announced on Thursday morning a total fire ban for five regions: the Murrayland, Riverland, Mid North, as well as the upper and lower South East.

The CFS warned of “extreme conditions”, with temperatures remaining high across the state, particularly along the border with Victoria.