The Bureau of Meteorology has forecast low to severe heatwaves across the continent from Thursday, starting in Western Australia - where some areas may swelter up to 50 degrees - and moving across South Australia, Victoria and Tasmania.

Inland parts of NSW and Queensland have also been forecast to hit temperatures in the high 30s and low 40s on Friday and Saturday.

BoM senior meteorologist Miriam Bradbury told ACM a low intensity heatwave would be covering all of Victoria, Tasmania and parts of NSW over the coming days and could potentially become severe during the weekend.

"Over the next couple of days those areas of low intensity heatwave are going to become much more extensive, pretty much covering all of Tasmania, Victoria and eventually NSW through the weekend as well," she said.

"We're going to start to see a few pockets of severe intensity heatwave across north-east Tasmania and parts of Victoria including the Melbourne area, and south-east NSW."

Ms Bradbury said BoM had issued warnings for Western Australia, South Australia, Tasmania, Victoria and NSW.

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She said regions including the Pilbara and Kimberley in WA were especially warned to brace for extreme high temperatures.

"Through parts of the Pilbara, we are actually expecting the temperatures to get even higher across the next couple of days with some parts expected to reach 47, 48 degrees," she said.

"It is possible we could see 50 degrees in some remote locations."

Ms Bradbury said south and south-east parts of the country should see temperatures six to 12 degrees above average - ranging from the high 30s to low 40s - but would later experience a cool change.

"We have a weak cold front moving across the south-east Friday going into Saturday so that means a little bit of relief for south-east South Australia, Victoria and Tasmania," she said.

"Adelaide, Melbourne and Hobart are going to move into some slightly more comfortable conditions over the weekend but because it's a weak front it's going to struggle to push inland.

"Eastern and northern NSW, and southern Queensland are going to remain very hot going through the later part of the weekend and into early next week."

She said BoM recommended people keep an eye on the warning updates and forecasts for their area and follow heatwave safety advice including staying inside, using fans and air conditioners and staying hydrated.