The Bayindeen bushfire raging northwest of Ballarat has burnt through more than 21,300 hectares, with forecast temperatures in the high 30Cs and wind gusts of up to 80km/h expected to fan the flames.
The danger is set increase from midday on Wednesday and authorities say the fire could rip through the communities of Beaufort, Elmhurst, Amphitheatre, Lexton, Learmonth and Clunes.
Country Fire Authority chief Jason Heffernan is issuing a last-ditch plea for residents to evacuate the fire zone, as no houses are designed to survive catastrophic conditions.
CFA Deputy Chief Officer Rohan Luke briefs NSW Rural Fire Service about the bushfire threat. (Con Chronis/AAP PHOTOS)
"Unless your property is immaculately prepared and you have firefighting resources available, and that you are fit and mentally capable to sustain a long duration firefight in protecting your own home, my strong advice to community is leave early," Mr Heffernan told ABC TV on Wednesday morning.
He said a cloud band over western Victoria had suppressed conditions during the morning but as soon as that breaks down scorching temperatures were set to kick in.
"Today unfortunately there's real potential for thunderstorm and dry lightening as well, which could introduce further fire into the landscape," he said.
The areas with an extreme fire danger rating on Wednesday are Mallee, Northern Country, North Central, Central and South West regions.
Mildura is set to reach 44C and other areas are also expected to creep into the 40s before a cool change in central parts of Victoria after 8pm AEDT.
Residents fleeing danger zones have been urged to go to built-up areas such as Ballarat, Ararat and Maryborough.
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 - Advice for Bayindeen-Rocky-Road. You should Stay Informed. For more info: — VicEmergency (@vicemergency) https://t.co/QTWFwsEKur #vicfiresFebruary 27, 2024
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 110 of its firefighters to help battle the Bayindeen blaze, 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.
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.
The Bayindeen fire in Victoria 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.