Temperatures in parts of New South Wales and Queensland are tipped to climb to nearly 50C in the next week as Australia's long, hot summer gets longer and hotter.

An heatwave is sweeping across the country's east this weekend, and northwest NSW and southwest Queensland will bear the brunt.

Birdsville, in Queensland's far west, is tipped to reach 48C on Tuesday.

The Outback town has sweltered through extreme temperatures, with just one day below 40C since January 15. Night-time temperatures have barely dropped below 30C. On Tuesday the Outback NSW town of Bourke is also tipped to reach 46C.


The town has had a week of temperatures in the low to mid 40s and NSW Bureau of Meteorology forecaster Jordan Notara said a cool change was a long way off.

"Really there isn't any major relief for the western arts of NSW and the north west," he said.

Sydneysiders, fresh from the hottest January on record, are again set to swelter now a brief respite of cooler days and nights has ended.

Temperatures in Brisbane and on the Gold and Sunshine coasts are tipped to reach the low 30s for the next few days.

Queensland Bureau of Meteorology forecaster Rick Threlfall said the sustained heatwave in Queensland is unusual.

"Normally you get a heatwave for a day or two before a cool change comes through. But there's no sign of any cool change until next week.

"It will get gradually hotter and hotter each day."

Meanwhile, last night large areas of northern and central NSW were headed for stormy weather, said the Bureau of Meteorology.

Severe thunderstorms with destructive winds, heavy rain and large hailstones are expected over parts of the Mid North Coast, Hunter, Northern Tablelands, Central Tablelands, North West Slopes and Plains and Central West Slopes and Plains.

- news.com.au, AAP