Sydney  - The enormity of south-east Australia's forest fires was revealed Sunday, with as many as 40 people believed dead, hundreds of houses destroyed and swathes of countryside turned to ash.

The official death toll from Saturday's inferno stands at 25, but police expect the number to rise above 40 as daylight allows them to pick through the wreckage of homes, sheds and vehicles.

More than 150,000 hectares has burned in the hinterland north of Melbourne, the capital of Victoria state.

"At this stage, to have 25 confirmed deceased, that gives me great concern that the numbers are going to get substantially higher as the day goes on, as we're able to get into the fire zones behind the fires to do those searches," Victoria Deputy Police Commissioner Kieran Walshe said.

The bodies of six people were recovered from a burned-out car in Kinglake that apparently failed to outrace the smoke and flames.

A caller to local radio who identified herself only as Georgina said her town of Strathewen, near Kinglake, was unrecognizable.

"It's just absolute devastation and people have seen things today that have been absolutely horrific," she said. "The school is gone, the hall is gone - some people left it too late. We've lost friends and we're just waiting for more - children, loved ones."

Victoria state Premier John Brumby said strong winds in tandem with fiery temperatures combined to create tinder-box conditions that a volunteer army of 30,000 firefighters backed by 37 water-bombing aircraft could simply not match.

"Some of these fires just weren't possible to control," he said from the goldmining town of Bendigo, where deaths were reported. "You've had firefighters that were literally facing flames that were four storeys high."

Melbourne, Australia's second-largest city, recorded its hottest February day on Saturday, with the temperature above 46 degrees. Inland of the port city of over 3 million people, the heat was even higher in the southern hemisphere summer.

Officials had warned of a possible repeat of the Ash Wednesday blazes in 1983 that left 75 people dead and destroyed thousands of houses.

"It's just a day, I hope in my lifetime is never repeated," Brumby said. (dpa)