An extreme heatwave is on the way for Australia's east coast with temperatures set to crack 40C -- and it's still Spring.

Residents across Victoria, New South Wales, South Australia and Queensland have been warned scorching temperatures are on the way.

And experts say November records could be smashed.

The Bureau of Meteorology described the weather event as "severe" with temperatures to tip 44C in Mildura and Swan Hill on Saturday.

Scorching temperatures to lash Australia’s east coast this weekend. Picture: BOM
Scorching temperatures to lash Australia’s east coast this weekend. Picture: BOM

Even Melbourne is heating up with a 34C forecast for Friday, but a cool change will send temperatures southward with tops of 28C and 20C expected for Saturday and Sunday respectively.

South Australia will be the first state to be battered by the scorching temperatures as a hot air mass moves across from Western Australia.

Adelaide is facing temperatures in excess of 40C on Friday and Saturday but a cool change is in sight with a top of 23C forecast for Sunday, the Bureau reports.

More regional parts of South Australia will be pummelled by unbearable temperatures with 46C forecast for Cooper Pedy and Port Augusta on Saturday.

A fire warning has also been issued for parts of the state, including in the Mount Lofty region where the danger rating is "extreme".

In NSW, Sydney will reach 33C on Saturday and 39C on Sunday while Western Sydney will cop temperatures of 41C on Saturday.

Residents of regional areas like Broken Hill and Dubbo will melt in temperatures of 43C and 40C respectively.

BOM said NSW is expecting "very hot days for the end of Spring" as well as some warm nights.

"Windy conditions will see fire dangers rising. A gusty southerly change along the coast on Sunday should bring cooler conditions there but northern NSW remaining very hot into next week," the Bureau said.

In Queensland, Brisbane will be a little cooler than other capital cities with tops of 30C and 31C expected on the weekend.

But temperatures could exceed 40C in inland areas.

Milder conditions are expected in other parts of the nation including Perth with 19C and rain forecast for Monday after a weekend of temperatures hovering in the low 20s.

Originally published as Extreme heatwave smashes Australia