The Bureau of Meteorology has declared a severe heatwave for much of South Australia next week - the first under a new national modelling system.
Parts of the state including Adelaide, Renmark and Port Augusta are preparing for five consecutive days of 40 degrees Celsius or higher.
The model has three levels of severity - heatwave, severe heatwave and extreme heatwave - and uses average temperatures of locations across the state to determine whether those areas will experience unusually high temperatures.
Manager of weather services at the bureau in Adelaide, John Nairn, .
"We've seen severe heatwaves and in fact extreme heatwaves in Queensland over the Christmas - New Year break and that heatwave has not gone away," he said.
"It's tracked around to the Top End so Darwin saw it recently. Now it's in Western Australia.
"That heat hasn't left Australia yet. It's coming back into South Australia."
Mr Nairn says high minimum temperatures are also expected, making conditions very uncomfortable before a change is expected to move through on Friday.
© ABC 2014
10:43 EDT A two-year-old boy has died and a girl has suffered serious injuries after a tree fell on their house at The Patch in the Dandenong Ranges, east of Melbourne, as severe thunderstorms swept through Victoria last night.