People living in high bushfire-risk areas in Victoria's north and north-west have been urged to leave their homes as soon as possible as the region faces the worst fire conditions in 10 years.

A Code Red – the state’s highest bushfire warning level – has been declared across the Mallee and Northern Country regions for Thursday.

It is the first time a Code Red has been declared in Victoria since 2010. A total fire ban across the state has also been declared.

A fire threatens homes at Hepburn, Victoria, in February this year. Credit:Adrian Hyde

"Do not be there. If a fire occurs, you will not survive," Steve Warrington, the CFA’s chief officer, said on Wednesday.