Locals dive for swim and shade as heatwave keeps grip

For the past week, news reports on the heatwave cooking the continent have focused obsessively on which temperature records have fallen in what town.

But records are meaningless to the residents of Menindee, which sits on the banks of the Barka-Darling River in far west NSW.

Just go outside. A mounted temperature gauge, which is not in the shade, will tell you the story: well over 50C.

It's much safer to stay indoors - and that's what most people are doing.

Michelle Kelly, manager of the Mirrimpilyi Muurpa-nara Aboriginal Corporation, said the night brought little relief, with the mercury barely dropping.

"There's been instances where the electricity hasn't been strong enough to work the air-conditioning, so people are relying on fans," she told AAP.

"People are just checking up on each other, especially the elderly, to make sure they're comfortable and have enough water."

On a sheep station between Ivanhoe and Balranald, Kate Finch said the ground-level temperature had at times exceeded 60C.

"I've officially said Broken Hill's got nothing on this," she said.

Broken Hill hit 47.8C on Tuesday - the town's hottest day on record. By Thursday, the edge had hardly come off, with the temperature nudging 46C in the late afternoon.

Ms Finch said it was an education for her 18-year-old son, who was taking a gap year on the farm after completing high school.

"The hottest awakening for him is the realisation that farm work doesn't stop when it's 50C," she said.

"You've got to keep going, because if you don't drop feed (the stock), they're going to die.

"It's a lot to put on someone's shoulders at a young age."

At night, the family plays Scrabble to relieve the tedium while relieving pressure on power use to safeguard the air-conditioning.

"You just pray it stays on at night," Ms Finch said.

From Queensland to South Australia, states are roasting in an extended heatwave expected to persist into the weekend before easing.

Heat warnings have been issued for Victoria, NSW, Queensland, South Australia and the ACT, with the Bureau of Meteorology expecting very hot temperatures to persist across western NSW and Queensland on Friday.

A spokesperson for the bureau said the frequency, duration and intensity of heatwaves had increased across Australia since 1910.

There had been an acceleration of events since the 1950s, with particularly high rates of intensification in the 2000s, and the number of severe and extreme heatwave days was projected to increase, the spokesperson said.

Australia has about four severe or extreme nationally averaged heatwave days per year.

The nation is projected to experience more than double the number of severe or extreme heatwave days per year with 2C of global warming.