Premier Daniel Andrews warned people to stay alert because Thursday was likely to be the last day of respite for fire-ravaged eastern Victoria.
Source: NEWS CORP AUSTRALIA/STATE CONTROL CENTRE MEDIA
"Messages will be sent out Thursday and Friday this week. They are about life and death, and people need to remain vigilant," Mr Andrews said on Tuesday.
"This is not over by a long shot."
The scorching conditions have also seen the cancellation of the electronic music festival Rainbow Serpent, which was planned for the Australian Day weekend.
Rainbow Serpent follows Falls Festival and A Day On The Green as the third Victorian music festival cancelled due to the bushfires.
Other events such as the Karkarook Parkrun and Couta Boat Classic have also been cancelled because of the blazes.
The Bureau of Meteorology on Wednesday issued an extreme fire danger warning for the north of the state on Friday, with a severe warning for the Mallee and northeast districts.
Temperatures nearing 40C are also forecast in some areas on Friday, along with northerly winds, ahead of a change in the afternoon.
People in Carboor and surrounding areas in the state's northeast were advised to leave late on Wednesday as spot fires from an out-of-control bushfire headed towards homes.
Source: Australian Department of Defence
Earlier on Wednesday, Emergency Services Minister Lisa Neville had stressed that people in fire-affected areas should leave before fire conditions worsen.
"The safest place to be is outside those fire-affected areas and in built-up areas," she told reporters.
Bushfires have burnt more than 1.2 million hectares across Victoria, isolating towns and destroying hundreds of properties.
Three people have died in the fires, with the third victim confirmed on Wednesday.
Forest Fires Management worker Mat Kavanagh, 43, died when his vehicle crashed on the Goulburn Valley Highway on January 3.
Authorities have urged the organisers of a climate protest planned for Melbourne's city centre on Friday night to postpone or call it off, or restrict it to one area.
Acting Assistant Commissioner Tim Hansen claimed it was bad timing for a protest because it would stretch police resources when fire conditions are likely to worsen.
But the protest's organisers, Uni Students for Climate Justice, on Wednesday doubled down on their planned protest, claiming "huge support for a demonstration to put pressure on the government and fight for climate justice".
Meanwhile, 200 evacuees and 66 volunteer firefighters who left Mallacoota on HMAS Choules on Tuesday arrived at Hastings on the Mornington Peninsula on Wednesday afternoon.
More than 4000 people were originally stuck in Mallacoota, while the final 142 believed to remain stranded are expected to be airlifted out when conditions allow.