Authorities urged Australians on Friday to evacuate parts of the eastern states of Victoria and New South Wales to escape bushfires they fear are set to burn out of control this weekend.
In a harbinger of the searing conditions expected, a number of fires burnt out of control in South Australia as temperatures topped 40 degrees C (104 F) across much of the state and strong winds fanned flames.
Victoria declared a state of disaster across areas home to about 100,000 people, with authorities urging people to evacuate before a deterioration expected on Saturday.
"If they value their safety they must leave," Michael Grainger of the state's police emergency responders told reporters. "I'd suggest personal belongings are of very, very little value in these circumstances.
"These are dire circumstances, there is no doubt."
Weather officials on Friday rated the danger from fire "very high" to "extreme" in most districts in South Australia, with a similar outlook for New South Wales and Victoria on Saturday.
At the summer holiday peak, authorities have advised tens of thousands of holidaymakers and residents to leave national parks and tourist areas on the south coast of New South Wales, where a week-long state of emergency has been called.
A death confirmed on Friday takes the state's toll this week to eight. Two people have died in Victoria, and 28 are unaccounted for.
In Victoria, naval vessels Choules and Sycamore started evacuations of about a quarter of the 4,000 people stranded on a beach in the isolated town of Mallacoota.
Since Monday, wildfires have killed ten people in New South Wales and Victoria, with 28 still missing in the latter.
With roads blocked, sea transport and some airlifts are the only way out of the stricken town, although heavy smoke prevented flights on Friday.
People in the fire-devastated New South Wales town of Cobargo angrily confronted Prime Minister Scott Morrison during a visit on Thursday, with one shouting that the leader should be "ashamed of himself" and had "left the country to burn".
Thousands of people had already been evacuated from East Gippsland in Victoria, one of the largest such exercises since more than 35,000 people evacuated from the northern city of Darwin in the aftermath of cyclone Tracy in 1974.
Morrison's conservative government has long drawn criticism for not doing enough to battle climate change as a cause of Australia's savage drought and fires.
This season's fires have scorched more than 5.25 million hectares (13 million acres) of bushland, with 1,365 homes destroyed in New South Wales alone, including 449 this week on the south coast.