The Bureau of Meteorology is forecasting maximum temperatures as high as 40 degrees in northern Victoria on Thursday.
The bureau is warning of an elevated fire danger on Thursday accompanying the heat.
The forecast for Shepparton is 37, Kyabram 38, Ecghuca 39, Benalla 35 and Kerang 39.
A change coming through on Friday is likely to bring temperatures down for the weekend.
The Bureau of Meteorology's Richard Carlyon on Monday said Mildura is expected to swelter in 41C temperatures on Thursday.
Melburnians will enjoy a sunny 33C but are warned to expect an uncomfortable evening, with the mercury to stay in the 20Cs overnight.Thursday is due to be Melbourne's hottest day since March and northerly winds will see fire danger ratings elevated for most of the state.
Mr Carlyon says the sticky weather will be short-lived, with a cold front expected to bring thunderstorms and up to 25 millimetres of rain once the cool change arrives around 1pm on Friday.