Victorians under threat from bushfires are facing their last chance to leave as catastrophic conditions descend on the state’s west.

The Bayindeen fire still raging northwest of Ballarat could rip through areas including Beaufort, Elmhurst, Amphitheatre, Lexton, Learmonth and Clunes.

Residents have been told to evacuate before midday Wednesday, with temperatures forecast to hit the high 30s and wind gusts of 80km/h expected to fan the flames.

The fire had burned through more than 21,300 hectares as of Tuesday.

The areas with an extreme fire danger rating on Wednesday were the Mallee, Northern Country, North Central, Central and South West regions.

Mildura was set to reach 44C and other areas were also expected to creep into the 40Cs before a cool change approached central parts of Victoria after 8pm.

Residents fleeing danger zones were urged to go to built-up areas such as Ballarat, Ararat and Maryborough.

Victoria Police strategic commander Jason Templar told a Pyrenees Shire Council meeting at Beaufort on Tuesday afternoon rapid deployment teams would be ready to close roads at the incident controller’s behest on Wednesday.

“The messaging around being out and being out early is so important because once those roads close, that’s it,” he said on Tuesday.

“Today or early tomorrow morning is the time to get out … and the reason we close them is purely for public safety, it’s too dangerous to be on those roads.”

Beaufort’s urgent care centre was closed on Wednesday and the Bayindeen bushfire threatened to cut power to homes if it came over the Western Highway.

Bushfire ‘beast’

Pyrenees Shire Council mayor Robert Vance warned his constituents, “this beast is a reality”.

“When the beast is gone (and) he’s blacked out, we’ll be around to help everybody,” he said.

About 500 firefighters were again expected on the ground, with more than 60 aircraft ready to fight the blaze and any fresh fires.

The NSW Rural Fire Service – which has deployed 25 fire trucks and 110 of its own firefighters to help battle the Bayindeen blaze – has additional aircraft on standby close to the Victorian border.

Extreme fire danger was also expected for much of eastern South Australia on Wednesday, with Emergency Services Minister Joe Szakacs warning the state’s firefighters were facing some of the harshest weather this summer.

Seven South Australian districts had an extreme fire danger rating on Wednesday.

“It’s entirely reasonable for the community to have enjoyed what has been some respite this summer, and we are days away from autumn,” Mr Szakacs told reporters.

“(But) complacency must be parked to the side. We are, as a state, facing some serious conditions.”

The Bayindeen fire in Victoria has so far destroyed six homes but more are expected to be accounted for once conditions subside.

-AAP