Queenslanders to sweat under heatwave while humidity is expected to trigger thunderstorms

One Australian state is forecast to sweat under a heatwave that may whip up a fresh wave of severe thunderstorms this week.

Queensland is set to face temperatures nearing 40 degrees in some parts of the state and the conditions could trigger downpours, fast winds and storms.

The Bureau of Meteorology has issued a three-day heatwave warning for Queenslanders, with conditions forecast to ease by Tuesday.

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Areas most impacted by the blistering heat are Mt Isa, Winton, Longreach, Moranbah and Birdsville.

Tomorrow will see the worst of the heatwave for some regions including the south-east.

The Bureau warned the heatwave could ease later in the week for the state's east coast but could persist in isolated areas in the central and western districts.

The severe humidity is predicted to trigger thunderstorms across the south-west and inland regions today.

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A severe heatwave warning has also been issued for the Pilbara, Gascoyne, South Interior and Central West areas in Western Australia, with conditions set to continue until Tuesday.

Severe thunderstorm warnings for parts of NSW were cancelled on Friday but forecasters still cautioned parts of Australia were in for a wet weekend.

Showers are expected in Sydney later today.

Storms and some showers are forecast in Alice Springs and Darwin in the Northern Territory too.