A change of weather in Victoria’s bushfire-besieged west threatens to make the situation more difficult for firefighters.

The Bureau of Meteorology warned of a south-westerly change forecast for early evening on Wednesday, while also saying there was a chance for dry thunderstorms in the early morning, which could also include damaging wind gusts.

The Country Fire Authority’s chief officer Jason Heffernan said the wind changes were a concern.

“Things will heat up very quickly during the day and around lunchtime we’ll hit that peak, but that late change today won’t come through until probably after dark,” he told 3AW on Wednesday.

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“The safest advice under today’s conditions is to please leave and be gone by about lunchtime.”

Communities north-east of Ballarat including Waterloo, Amphitheatre, Raglan and Glenlogie are being told to flee, with conditions not safe to return to.

However, some Victorians in these areas have decided to stay put.

The Bayindeen bushfire raging north-west of Ballarat has burnt through more than 22,000 hectares ahead of forecast temperatures in the high 30Cs and wind gusts of up to 80km/h on Wednesday afternoon.

Containment lines have been erected around the fire’s entire 157-kilometre perimeter and pockets of scrub burned out overnight in the north-west and east of the blaze.

“We have a control line right the way around the fire,” incident controller Jarrod Hayse told reporters in Ballarat on Wednesday afternoon.

“For every hour that this fire doesn’t reach control lines, we’re in a really good position.”

The danger was set to increase from midday, with authorities warning the fire could rip through the communities of Beaufort, Elmhurst, Amphitheatre, Lexton, Learmonth and Clunes.

Rain was falling in Beaufort just before the deadline to leave for residents and others in the Wimmera to the state’s west, where catastrophic conditions have been forecast.

But Hayse said the cloud cover wasn’t expected to last and warned it could bring dry lightning.

“Our confidence is not that high in making sure we won’t have any breaches of containment today,” he said.

“We’re really up against significant fuel, weather and topography issues.”

Authorities have been pleased with residents in the danger zone heeding advice to get out of town but some have decided to stay.

Beaufort local Kevin, who did not wish to have his surname published, said he couldn’t bear to see his property and large shed burn down after fire wiped out his family home in New South Wales’ Blue Mountains in the 1990s.

“I don’t want to lose my house again,” he told AAP.

“The insurance company don’t want to know about it.”

Most stores in the small town were shut aside from a few cafes, as local Country Fire Authority members departed for the fire ground on Wednesday morning.

Kevin, who has family members in Melbourne and Phillip Island, said about half a dozen homes on his street had not been vacated.

“They couldn’t afford to buy another one,” he said.

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

Beaufort’s urgent care centre was closed on Wednesday, with the bushfire having the potential to cut power to homes if it came over the Western Highway.

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

Mildura is set to reach 44 degrees and other areas are also expected to creep into the 40s before a cool change in central parts of Victoria after 8pm AEDT.

More than 60 aircraft are ready to fight the blaze and any new fires.

The NSW Rural Fire Service has deployed 25 fire trucks and about 110 firefighters to help, while aircraft are on standby near the Victorian border.

Interstate firefighters were among 160 people who spent the night at a base camp in Ballarat, which can house up to 300 people in tents.

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

More than 100 stock animals were killed in the fire or are missing, according to the State Control Centre.

The minimum security Langi Kal Kal prison in Trawalla, 40 kilometres west of Ballarat, has been evacuated, with inmates moved to the Western Plains Correctional Centre at Lara.

-with AAP