New South Wales to swelter through scorching temperatures

New South Wales is forecast to swelter through a heatwave next week, with temperatures expected to nudge 40 degrees in parts of the state.

The mercury will climb to the mid 30s in Sydney on Monday, while the city's western suburbs could record about 38 degrees.

Bureau of Meteorology meteorologist Miriam Bradbury told 9News.com.au the low-intensity heatwave will start building on Sunday after cooler and damper conditions tomorrow.

READ MORE: Heat especially taxing for Australians on income support: survey

"The temperatures will rapidly rise to the low and mid thirties across many parts of the state on Monday."

A low pressure system across inland NSW will drive east in coming days and cause the mercury to spike.

In coastal areas, Wollongong is set for a top of 34 degrees, Nowra 35 degrees and Bega 31 degrees.

But inland areas will also swelter, with Broken Hill forecast to hit a maximum of 37 degrees on Sunday.

READ MORE: How to cool the house down

The good news is the spate of scorching conditions will be short and sharp.

"By Tuesday the temperatures will slip back to the low thirties and from then they will drop to the mid and high twenties," Bradbury said.

Meanwhile, an increased fire danger warning has been issued for large parts of Australia for the autumn months.

The National Council for Fire and Emergency Services has warned large parts of NSW, South East Queensland and Western Australia have above-average potential for bush and grass fires.

"Climate outlooks for autumn suggest a change to drier landscapes, with much of the country likely to see below average rainfall and normal-to-above-normal temperatures," AFAC said.

"Rainfall over the last couple of seasons has created favourable growing conditions and fuels in these areas are re-accumulating quickly."

Sign up here to receive our daily newsletters and breaking news alerts, sent straight to your inbox.