Orange will be spared the worst of the heatwave with the Bureau of Meteorology predicting a top of 33 degrees on Friday, 24 degrees Saturday before a welcome drop to 26 degrees on Sunday.

"The hot air mass that's over central parts of the country is expected to challenge quite a few records, although it's not affecting most of the capital cities," Weatherzone meteorologist Ben Domensino said.

Instead, the central parts of Australia will bear the brunt of the hot weather. Maree and Moomba in South Australia look likely to experience a scorching 49 degrees, with Moomba closing in on its record of 49.5 degrees, and Queensland's south-west town of Birdsville is set to reach 48 degrees.

Temperatures in Alice Springs may also near its hottest ever record of 45.2, with the Bureau of Meteorology predicting the town will reach 43 degrees.

Mr Domensino warned that certain parts of Queensland could experience the longest stretch of scorching days on record, with the town of Longreach expected to have nine consecutive days in 44-46 degree heat.

"For some places, particularly western Queensland, it'll be the most intense heatwave for some parts of the state in more than 50 years," Mr Domensino said.

South Australia's Roxby Downs is forecast to hit 45 degrees, while the more northern Oodnadatta could reach a high of 48 degrees.

Leigh Creek, some 550 kilometres north of Adelaide, could hit 46 degrees, potentially creeping past its 25-year standing record of 46.3.

By Friday, the heat will catch up with Bourke and Tibooburra in northwest NSW, with temperatures expected to hit 47 degrees.

The Bureau of Meteorology has also issued high and very high fire danger ratings across NSW, and not much rain is expected throughout the day. As of Wednesday evening, the Rural Fire Service said that there are no total fire bans in place in the state for the coming days.

Predictions for early next week suggest cooler weather on the way for NSW.

Weatherzone is published by Fairfax Media, the publisher of this website.