The Wimmera region in the state's west faces a catastrophic fire danger rating on Wednesday, with firefighters coming from interstate to help protect the area.
Five other regions are extreme, with a total fire ban declared for all catastrophic and extreme regions.
A Total Fire Ban has been declared for the Mallee, Wimmera, South West, Northern Country, North Central and Central fire districts for 28/02/24.— cfa_updates (@CFA_Updates) No fires can be lit, or be allowed to remain alight, in the open air from 12:01 AM until 11:59 PM. https://t.co/qTT4P4ne58 pic.twitter.com/8jJo3QDcctFebruary 26, 2024
Some 30,000 people in communities around two bushfires in the state's west will be sent alerts on Tuesday advising them of the danger and asking them to heed warnings to leave early.
Authorities have created a map of where the fire could potentially go, including towns such as Beaufort, Elmhurst, Amphitheatre, Lexton Learmonth and Clunes.
"Fire, spot fires and ember attack are quite possible in these areas, these could result in loss of homes, closure of roads and isolating communities," Emergency Management Commissioner Rick Nugent told reporters.
Country Fire Authority chief Jason Heffernan said the peak fire threat is expected from midday on Wednesday until about midnight.
He urged people planning to leave the area to get out on Tuesday night or early on Wednesday.
"I would not leave it any later than lunchtime because those weather conditions will become quite nasty from 12 o'clock onwards," he said.
Victorian premier Jacinta Allan said close to 100 school and early childhood facilities will shut on Wednesday while vulnerable people in aged care and hospitals have been taken away from the danger.
The Mallee region was slated to reach mid-40C and get winds of up to 45km/h on Wednesday while other parts of the state were also expected to creep into the 40Cs.
The threat comes as a watch and act alert remains for the wild Bayindeen fire, northwest of Ballarat, which had burned through more than 21,300 hectares as of Tuesday morning.
So far six homes and 10 other buildings have been lost to the fire.
Crews are coming from NSW to help the hundreds of firefighters on the ground who have been battling the blaze since it sparked on Thursday.
Comissioner Nugent said Wednesday's spike day could see the Bayindeen fire run again and head south before swinging back around.
Mr Heffernan warned power could be cut because of fires.
"No homes are designed to withstand those catastrophic conditions," he said.
"Tomorrow is the day to have a bushfire survival plan."
At the Bayindeen fire, efforts have been on building containment lines.
Crews were working day and night to try to get a consolidated line around the massive blaze but the steep landscape, unfit for fire trucks, has made it difficult to tackle.
There will be 66 aircraft available for Wednesday and NSW is strategically putting aircraft along its side of the border in case fires flare.
Watch and act warnings remain in place for residents of Amphitheatre, Elmhurst, Raglan, Waterloo and other areas, warning locals that it is still unsafe to return.
Three national parks have been shut, including the Grampians National Park which is popular with holidaymakers.