Firefighters in South Australia and Victoria are battling out-of-control bushfires, with warnings that conditions are the worst since Ash Wednesday in 1983.
The Adelaide Hills remained under threat tonight as a massive bushfire threatened dozens of communities just 26 kilometres from the city's centre, the ABC reported.
Dozens of homes were feared lost and lives remained in danger as the out-of-control fire burned on multiple fronts after an afternoon wind change.
Meanwhile, new fires had broken out in Victoria - among more than 300 fires in the state over the last two days.
Fire rages in South Australia
South Australian Country Fire Service (CFS) chief officer Greg Nettleton estimated the fire at Sampson Flat in the Southern Mount Lofty Ranges, north-east of Adelaide, had burnt close to 10,000 hectares.
Mr Nettleton said it may not be brought under control until early next week.
"We've got a lot of work to do out there, first of all in controlling the fire and then cleaning up all the insecure edges," he said.
"It will be affected by south-westerly winds through tonight which means the fire will travel in a north-easterly direction.
"We'll be working very hard to try and get that fire secured before hot and windy conditions that are anticipated on Wednesday."
Around 500 firefighters supported by 100 appliances and 14 aircraft were battling the blaze, with more personnel and trucks to arrive from New South Wales.
At least five homes had been destroyed and dozens more threatened.
Mr Nettleton said six volunteers had received medical treatment, mostly for smoke inhalation.
CFS assistant chief officer Rob Sandford said firefighters were doing their best "in what are the worst of conditions imaginable for firefighting ... We're thinking likely dozens of houses lost."
Police earlier declared the fire a major emergency, giving authorities the power to forcibly evacuate people or block them from entering the region.
The bushfire was burning freely towards townships and residents across the area were fleeing to safer ground, although some had chosen to stay and defend their homes.
The CFS urged locals in the affected areas to enact their bushfire survival plans.
It said a separate forest fire at Tantanoola in the state's south-east, which had burnt up to 700 hectares, had been slowed.
About 2000 firefighters attended dozens of incidents across South Australia today, with some sparked by lightning strikes as storms moved across the state.
New emergency warning in Victoria
A cool change, with strong winds and lightning, has been moving across Victoria as firefighters tackle a series of new fires breaking out in the west of the state and south-west of Melbourne.
Fire officials have stopped the spread of a bushfire threatening homes at Hastings, Bittern and Crib Point. An emergency warning issued earlier has been downgraded to a watch and act.
However the wind change pushed the fire towards houses south of Reid Parade and there has been some damage.
The watch and act alert for the towns of Moyston, Rocky Point, Willaura North, Maroona, and Langi Logan has been downgraded.
Firefighters have stopped the spread of the Moyston fire and rain has helped ease conditions.
The fire, one of more than 300 fires that have started over in the state over the past two days, has claimed one house and destroyed around 5000 hectares.
High temperatures continued to create dangerous conditions in other parts of Victoria.
Ambulance Victoria said paramedics attended several calls for elderly people suffering heat-related illness, as well as one drowning and four calls for children locked in cars.