Thousands of firefighters - including a team of New Zealanders - are battling 28 blazes burning out of control across the Australian state of Victoria.
The bushfires have burnt large swathes across the state, destroying homes and farms, in the worst fire conditions since Black Saturday five years ago.
There has been no official confirmation of the number of properties lost but reports say at least 10 homes have been destroyed.
High temperatures and strong winds fanned the fast-moving fires, as a weather change swept across the state bringing wind gusts up to 100 km/h.
Some of the fires got close to homes in northern Melbourne. Photo: AAP
A blaze at Morwell in the Latrobe Valley destroyed houses and affected the Hazelwood coal mine and part of the Maryvale paper mill. Morwell resident Simon Ellis told the ABC he saw three huge explosions as the fire burned near the Hazelwood power station.
Fire Services Commissioner Craig Lapsley said cooler temperatures on Monday would assist firefighters but the danger remained.
He said the major concern was fires burning in the outer metropolitan area, in the Latrobe Valley and in far east Gippsland, AAP reported.
While the fires are the worst in Victoria since Black Saturday, Mr Lapsley said they were far less devastating.
"It's not the same day as 2009 in the sense that 2009 was underpinned by 13 years of drought and also the fire danger indexes were off the scale."
Victorian premier Dennis Napthine said the response had been oustanding and had taken on board lessons learnt from Black Saturday.
"We now have better warning systems, we now have a better system of all emergency services agencies working together."
Mr Napthine paid tribute to the firefighters battling the blazes.
"Credit goes to our firefighters who are on the front line in these very dangerous conditions," he said.
The ABC reported Country Fire Authority chief fire officer Ewen Ferguson as saying police would investigate a number of suspicious fires, including one at the Morewell open-cut mine.
"There are definitely suspicious activities."
John Sutton, who is leading the more than 40 New Zealand firefighters in Victoria, said on Sunday the changing winds had made their job difficult.
In just one hour there had been an almost 180 degree change in the direction of one of the biggest fires, near the town of Orbost, from the north to the south, he said.
In South Australia, a fire that has consumed more than 30,000 hectares since it started three weeks ago has broken containment lines and is burning its way towards several towns north of Adelaide.
