Catastrophic fire conditions are tipped for parts of Victoria as Australia's southern states brace for hot, windy and dry weather over coming days.
Schools and national parks will close as Victoria faces the first catastrophic fire conditions since the Black Summer of 2019-20.
Tasmania, South Australia and Western Australia are also braced for extreme fire danger amid heatwave conditions.
Hot, dry and windy conditions are forecast across Victoria on Tuesday, with the possibility of thunderstorms and dry lightning.
A catastrophic fire danger rating has been declared for the Wimmera region, extreme in the Mallee and high danger rating for rest of the state except for East Gippsland.
A total fire ban is in place for most of the state.
Emergency Management Commissioner Rick Nugent said Tuesday's weather forecast, with some areas predicted to reach 40 degrees Celsius, would be challenging
"We're going to have an extremely hot, dry and windy day ... followed by thunderstorms and lightning," Mr Nugent said yesterday.
"We are doing everything possible to make sure we are well prepared to respond to any fires that may occur anywhere in the state."
Country Fire Authority chief officer Jason Heffernan said predicted conditions would be some of the most dangerous grass fire conditions since the Black Summer of 2019-20.
Black Summer was one of the most intense and catastrophic fire seasons on record in Australia.
Despite the catastrophic rating for Wimmera, he warned any areas from Melbourne to the west need to be alert to fire.
"Grass fires can be just as deadly as bushfires during the 2019-20 season, they move incredibly fast and can jump roads."
Tasmanians were also being urged to prepare for an increased fire danger over the coming days.
Tasmania Fire Service Deputy Chief Officer Matt Lowe said current weather conditions, combined with a dry landscape, meant fires could spread easily and become difficult to control.
"TFS are putting a temporary hold on issuing fire permits in the south and north of the state until 2am Thursday," he said yesterday.
"While we are not declaring a Total Fire Ban, we are asking people to think carefully before lighting campfires and using machinery, and if doing so please be extremely cautious."
South Australians are also bracing for a hot and dry Tuesday and extreme fire conditions.
Total fire bans have been declared today with extreme fire danger ratings for mid north, Riverland and Murraylands.
The South Australian Country Fire Service says "very hazardous" fire weather conditions are predicted.
The Bureau of Meteorology has also issued a heatwave warning for parts of Victoria, with conditions expected to ease with a cooler change from late Tuesday night through early Wednesday morning.
A severe heatwave warning is also in place for parts of Western Australia including Kimberley, Gascoyne, Central West and Great Southern Districts.