Millions of people are facing elevated fire danger as authorities warn there is plenty of fuel left to burn this season.
Fire authorities are on high alert as strong winds threaten to push dry heat and thunderstorms east from South Australia on Tuesday.
Extreme fire danger is forecast for much of Victoria, with temperatures in the mid to high 30Cs combining with hot, dry and gusty winds over parched fuel loads.
"The whole state is still a tinderbox," Emergency Management Commissioner Tim Wiebusch told reporters on Monday.
Parts of Victoria have not had meaningful rain for weeks, leaving abundant dry fuel despite major blazes already this season.
Victoria's west and southwest are particularly vulnerable, with authorities warning new fires could spread quickly.
"The winds will mean that this will be a challenging environment for firefighters right across the state," Country Fire Authority deputy chief officer Alen Slijepcevic said.
"A cool change is expected to reach Adelaide by mid-morning before sweeping into Victoria later in the day, bringing gusty winds, showers and thunderstorms."
The wind change is forecast to hit Melbourne in the early evening, followed by a band of rain over parts of southern Victoria.
Storms developing in western Victoria during the afternoon could be severe, with damaging winds, heavy rainfall and lightning posing further fire risks.
A total fire ban will blanket five of the state's nine districts, extending to the Wimmera, North Central, Central, South West and West and South Gippsland regions.
Major bushfires near Walwa in the northeast and Longwood in the state's centre were deemed under control on Friday, while the Otways blaze remains active.
Mr Wiebusch said fire authorities were optimistic the Otways fire would be brought under control this week, allowing recovery operations to begin.
High fire danger ratings are in place across much of South Australia, NSW and Tasmania for Tuesday.
Temperatures are expected to ease across South Australia, after the mercury edged towards 40C in the state's west on Monday.
Conditions should ease significantly by Wednesday, with 10C to 15C temperature drops forecast across much of the southeast.
