Australians brace for 'property loss or worse' as bushfires destroy homes

Australians in Victoria have been warned they should prepare for "property loss or worse" as much of the country faces extreme heatwave conditions.

Temperatures on Friday and Saturday are forecast to hit record highs for most states and territories, with Victoria and South Australia in particular bracing for dangerous fire conditions due to strong winds and hot temperatures.

A total fire ban is in place in Victoria and all regions across the state were given a "catastrophic" or "extreme" fire danger rating.

"Victorians should brace themselves for more property loss or worse," Country Fire Authority (CFA) chief officer Jason Heffernan told the Australian Broadcasting Corporation (ABC) on Friday.

"The conditions were extreme yesterday. They're catastrophic today," Heffernan said.

Temperatures in Melbourne are expected to hit 42C on Friday and while areas in north-west Victoria may reach 45C, a cool change is forecast in the south-west.

A bushfire near Longwood, central Victoria, has burnt through nearly 36,000 hectares, authorities said, with at least 20 homes in the small town of Ruffy destroyed.

Ruffy CFA captain George Noye said the town had been "severely" affected.

"The main street looks like a bomb's gone off, we've lost a school," he told the ABC.

"Some properties have lost everything. They've lost their livelihoods, they've lost their shearing sheds, livestock, just absolutely devastating.

"But thankfully, at the moment, no lives have been lost."

A statement from Victoria's state control centre on Friday said the Longwood fire was "incredibly dynamic, with the fire spreading in multiple directions" and may spread further than initial estimates.

Victoria Police Deputy Commissioner Bob Hill said three people - two adults and a child - remain unaccounted for in the Longwood area.

He said authorities spoke to them yesterday at their property, warning them to seek shelter as it was too late to evacuate. Fire officials returned later to find the home had burnt down but could not locate the three people.

"They may be safe, they may be alive, let's not get ahead of ourselves, but we are keeping an open mind," Hill said.

In the Australian Capital Territory, which includes the capital Canberra, a total fire ban was declared for the first time in six years.

Sydney will see the mercury rise up to 42C on Saturday, before dropping to around 26C by Sunday.

Another fire near Walwa, north-east Victoria, has burned through more than 17,000 hectares.

Heffernan urged all Victorians to be on high alert, not just those near active fires.

"That is how severe these conditions are at the moment, not only at the Longwood fire but across the state," he told the ABC.

"My message at the moment to Victorians is yes, we are talking about Longwood and Walwa, but we have many other fires that have started this morning in and around communities... I am expecting more as the day goes on."

In South Australia, local fire authorities said they had battled a number of small fires across the state overnight and temperatures were expected to hit 46C in some areas.