The national weather forecaster said the heat would be wide reaching, impacting central Western Australia, northern South Australia, southern Northern Territory, southern Queensland and NSW.

Low to severe intensity heatwave warnings are in place for all five states while locally extreme heatwaves could impact parts of far southwest Queensland.

“Widespread temperatures above 40C are expected across inland and eastern parts of Australia over the next few days, with some inland areas as hot as 49C,” a Bureau of Meteorology spokesperson told AAP.

“The heat will spread out to the coast, with Sydney forecast to reach 35C on both Thursday and Friday, while some of the western suburbs may reach 39C or even 40C.”

Temperatures in the high 30s are set to sweep across the NSW coast with Newcastle forecast for 39C on Thursday.

Inland areas of Southern Australia’s north, southwest Queensland and northwest NSW could swelter in temperatures in the mid to high 40s on both Thursday and Friday.

Queensland’s Birdsville is forecasting 49C for Friday.

Although widespread records are not expected to be broken, a few remote or inland locations could possibly set new records for maximum temperatures, the bureau said.

Cooler air developing in the south of Western Australia on Wednesday is set to gradually spread across the southern states on Thursday and Friday, ending the heatwave for many.

The cool change will mean cooler weather for almost all areas on the weekend.