Heat alert as states hit with scorching conditions

Much of NSW and parts of Queensland, South Australia, West Australia, the Northern Territory and ACT are copping soaring temperatures that are expected to intensify towards the end of the week.

Bureau of Meteorology senior meteorologist Miriam Bradbury said the hot weather had formed on the western side of the country and was gradually making its way eastwards.

"The heat is lingering over Australia and is being held in place by a couple of high-pressure systems," she told AAP.

"Those systems are slow moving ... usually we can wait for cold fronts to sweep the heat out but the high-pressure systems are holding it where it is."

NSW residents are in for a sweltering period, with a severe heatwave warning issued from Wednesday and expected to last well into the weekend.

On Wednesday, temperatures topped 37C at Grafton in northern NSW, 39C at Scone in the Hunter region and 40C in Wellington in the central tablelands.

Temperatures in the north and central west slopes and plains reached 38C and above at the hottest part of the afternoon.

The upper western NSW region copped temperatures higher than 40C, with Wilcannia recording 43C at 3pm.

Multiple WA towns including Wyndham, Halls Creek, Newman and Yalgoo reached a maximum of 42C.

The mercury also soared in South Australia, with Coober Pedy, Roxby Downs, Woomera and Moomba tipping 45C.

NSW Health urged residents to plan ahead and take steps to beat the heat as high temperatures linger during the next few days.

Heatwaves can particularly affect people aged over 65, babies, young children, pregnant women and the homeless.

Hot weather could put a strain on the body by exacerbating underlying health conditions, NSW Health executive director Jeremy McAnulty said.

"It is important for people to know the symptoms of heat-related illnesses and take precautions to keep themselves and their loved ones cool," he said.

"If they can, they should also take the time to check on vulnerable and elderly neighbours and family to ensure their safety in the heat."

While a cold front was expected to bring some relief for WA, the NT and South Australia at the weekend, cooler temperatures are not forecast for parts of NSW for a number of days.

"Sydney and parts of the east coast will feel relief from Sunday but the heat will linger in the inland, western part of NSW," Ms Bradbury said.

"It looks like those hot temperatures will continue until at least mid-next week."

Australian Associated Press