The blaze in the Grampian mountain range in the state’s west has so far claimed 24 homes and engulfed more than 120,000 hectares of farmland and bushland.
The towns of Wartook, Laharum, Pomonal and Brimbean were put on high alert alongside Halls Gap and Mirranatwa, where residents have been urged to keep watch for ember storms.
The Country Fire Authority (CFA) website says about 700 fire-fighters have been working to establish control lines.
"With expected hot weather and north-north-westerly winds all residents south and south-east of the fire should be on high alert for possible ember attacks," the website said.
The blaze in the Gampians is the largest of four major fires burning across Victoria.
Bushfires at Kinglake, 65 kilometres north of Melbourne, Moondarra State Park in Gippsland in the state’s east and another at Anakie, in the west, also remained out of control.
The Moondarra fire was also tipped to intensify on Thursday with high temperatures and strong, dry winds forecast.
"Fire behaviour on the Moondarra fire is expected to increase as the weather warms up this afternoon," the CFA warned.
"The fire is currently in excess of 13,000 hectares and has a perimeter of 95 km."
About 10,000 fire-fighters will be on the ground across Victoria on Thursday, the CFA numbers bolstered by about 200 New South Wales fire-fighters drafted in to help. A total fire ban was in force across Victoria.
Heavy losses
The CFA has released a list of the damage caused by the Grampians blaze, which flared up last weekend.
The fire, also known as the Mt Lubra fire, has claimed 67 farms, with stock losses of about 60,000 sheep, 500 cattle and 170 poultry.
The Victorian bushfires have so far claimed three lives.
A fire-fighter was killed in a truck roll-over in central Victoria, and a father and son died when their crashed vehicle was engulfed by the flames in the Grampians.
A trust fund has been set up for the family of volunteer fire-fighter Trevor Day who was killed when he was thrown from the truck while battling a blaze near Yea on Monday.
Three of his colleagues were injured, one critically.
CFA deputy chief officer Graham Fountain said no amount of money could replace a human life, but proceeds from the trust fund would help the Day family in future times.
The money comes on top of CFA compensation to be paid to the family - the amount has yet to be set.
Mr Day will be farewelled next Monday at a funeral service in Campbell's Creek, south of Bendigo.
Meanwhile, three fire-fighters have also been treated for chemical poisoning following a blaze on Wednesday at Romsey, 65 km north of Melbourne.
Paramedics were called to a farming property about 5pm (AEDT) when fire-fighters began experiencing symptoms after the blaze spread to a shed containing unidentified chemicals.
A Rural Ambulance Victoria spokeswoman said 30 fire-fighters were assessed and three of them were treated for nausea and throat problems.
Tasmania on alert
Tasmania is also on high alert with four fires burning out of control around the state.
At the mining township of Zeehan in the state's west fire crews were battling to gain control of a fire that has burned more than 3,000 hectares.
Bushwalkers were evacuated from Tasmania’s Southwest National Park when a separate fire drew near.
Meanwhile in Western Australia heavy rain has brought a reprieve to residents and fire-fighters battling a massive bushfire that had threatened three towns in the state's south-west.