More than 500 firefighters are tackling the blaze west of Ballarat that has torn through about 16,000 hectares.
Residents of Amphitheatre and Elmhurst have been warned it is still not safe to return to their homes, as authorities warn of worsening fire conditions this week.
Wednesday is of the most concern to firefighters, described as a "spike" day when the mercury is set to soar above 40C.
Premier Jacinta Allan said around 700 people were out on the fire ground to battle the blaze. (David Crosling/AAP PHOTOS)
The Bureau of Meteorology said these high temperatures will be joined by strong, gusty winds.
"All of the elements that do lead to dangerous fire conditions are starting to rear up again on Wednesday," senior meteorologist Angus Hines said.
"We've got many areas of western Victoria at extreme fire danger for Wednesday ... there's a possibility that even more areas could see that extreme fire danger rating or even a chance they could be upgraded to catastrophic fire danger."
Emergency Services Minister Jaclyn said 228 impact assessments have been done to date as efforts to suppress the fire continue.
Ms Symes said the CFA has expressed "grave concerns" about conditions on Wednesday, and warned residents to make preparations.
"Don't leave it to make decisions until its too late," she said.
Wednesday is of the most concern to firefighters, with the mercury set to soar above 40C. (James Ross/AAP PHOTOS)
Ms Symes said the bushfires could continue to burn for some time, and crews will be rotated to prevent fatigue.
"Even without Wednesday's weather, that fire will not be put out until about three weeks," she said.
"We know that our first responders are going to be out in the field for many days and we want to make sure that we're looking after their health and wellbeing."
People told to evacuate earlier in the week have not yet been able to return to their homes.
They include residents from Avoca, Bayindeen, Chute, Elmhurst, Mount Lonarch and surrounds, Main Lead, Raglan, Middle Creek, Waterloo, Glenlofty, Glenpatrick, Glenshee, Green Hill Creek, Nowhere Creek, Crowlands, Eversley, Landsborough, Percydale and Warrenmang.
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