Australians have been warned to brace themselves as a heatwave intensifies this weekend, with catastrophic fire danger in some areas.

The mercury will exceed 45C in large swathes of New South Wales on Saturday, while in parts of South Australia, Victoria and south-east Queensland residents will also swelter through temperatures in the 40s.

The Bureau of Meteorology said the heatwave would be at its worst throughout New South Wales with the small north-western town of Ivanhoe tipped to reach 48C.

“We will see large areas above 45C for much of western New South Wales, west of the Ranges,” Senior Forecaster Stephen Wood told The New Daily.

Soaring temperatures will have some flocking to the beach. Photo: Getty

“Major towns like Dubbo, Orange, Griffith, Cobar, Broken Hill and even down towards Mildura will be about 43C.

“Those western suburbs of Sydney, around Liverpool, Penrith and Richmond will be reaching 45C, and up the coast towards Newcastle will as well.”

The rest of Sydney is expected to hit 39C on Saturday, while the mercury will reach 36 in Brisbane, 41 in Canberra and 34 in Adelaide.

Fire warnings

The NSW Rural Fire Service issued a total fire ban for the entire state over Saturday and Sunday, warning conditions were primed for bushfires and urging residents to be vigilant.

A catastrophic fire danger rating has been flagged from the state’s Central West to the Hunter region for Sunday.

Today's 4pm temperatures show the true extent of heat across the country. Large areas above 40°C. #Heatwave. https://t.co/ByG5YyVjFH pic.twitter.com/hw2k7r5w6Q

— Bureau of Meteorology, Australia (@BOM_au) February 10, 2017

The danger would increase across southern parts of the state from Friday, said NSW Rural Fire Service Commissioner Shane Fitzsimmons.

“If the forecast eventuates we’re likely to see catastrophic fire danger develop in some areas including the Hunter,” RFS Commissioner Shane Fitzsimmons said in a statement.

RFS Inspector Ben Shepherd said recent heat had dried out substantial parts of NSW.

“In the next few days we’re likely to experience some of the highest fire dangers for this season,” he said.

BOM forecaster Stephen Wood said the hot conditions were the result of trough directing north-westerly winds in New South Wales.

Catastrophic fire warnings were not common at this time of the year, he said.

“It’s quite late in the season to have something like this, that’s for sure,” Mr Wood said.

Blackout avoided

On Friday, Sydney avoided a major power blackout, which had been feared, despite temperatures hitting 45C in some areas.

There were some outages, with about 11,000 in the Sydney suburbs of Burwood and Strathfield affected by a network fault, and AGL Energy cutting power to an aluminium smelter in the hinter Valley in order to avoid mass electricity blackouts.

The NSW Government said power demand was at record levels and urged residents to use electricity sparingly.

Experts have warned of a nationwide power blackout if energy policies are not addressed. Photo: AAP

Friday’s conditions were considered a test of the state’s coal-dependent system, following a blackout in South Australia, where coal has been swapped for renewable energy.

The power grid had been sured up by the Queensland network, according to Queensland’s Energy Minister Mark Bailey.

“To be quite frank, without Queensland power today NSW would be in absolute dire straits,” he said on Friday.

Hospitals are also bracing for an increase in admissions this weekend after nearly 200 people were treated for heat-related illnesses in South Australia over the second half of the week.

A cool change is expected to sweep through Victoria, parts of New South Wales and South Australia on Sunday, but the heatwave will persist throughout Western Sydney.

Mr Wood said relief would arrive on Monday with cooler temperatures forecast in most areas.

While Australia’s east coast sweltered on Friday, Perth endured 114mm of rain from Thursday morning to Friday, the city’s wettest day since February 1992.

And in Tasmania, snow was forecast for Saturday at Hobart’s Mount Wellington and in central areas of the state.

NSW BAKES

FIRE WARNINGS
* A total fire ban has been declared for the entire state on Saturday and Sunday
* A potential “catastrophic” fire danger warning on Sunday around the Hunter, from the coast, mid-north coast, out through the Central Tablelands, the top end of the greater Sydney region and out to the central west
POWER
* Electricity supply conditions are expected to be tight but the threat of rolling blackouts to meet demand has been downgraded.
* Residents still being urged to limit electricity use on Saturday
SPORT
* NRL – All three trial games to go ahead on Saturday, Canterbury clash against Penrith pushed back to 7.45pm
* Cricket – Sheffield Shield match between NSW and Queensland to continue with increased drinks breaks. Cricket NSW has cancelled all grades of Premier Cricket
* Soccer – Jets-Victory A-League match in Newcastle postponed to Monday. Football NSW has cancelled all Saturday trial games for under-18s and below while under-20s and first grade trials shifted to evening start times
* Racing – Saturday’s race meeting at Royal Randwick postponed to Monday

-with AAP