At least 14 people have died in a day of devastating fires across Victoria.
Victoria police confirmed the deaths on Saturday night and said they fear the figure may be more than 40.
Deputy police commissioner Kieran Walshes said all the deaths were in a massive blaze northwest of Melbourne - six at Kinglake, four at nearby Wandong, three at Strathewen and one in Clonbinane.
Mr Walshe believed the Kinglake victims were all in the same car.
He believed arsonists are responsible for some of the nine major fires ripping across the state.
At least 100 homes have been destroyed as nine major blazes burnt out of control across Victoria in the worst fire conditions in the state's history.
Victorian Premier John Brumby described it as a "terrible, terrible day.”
“Tragically we have had 14 confirmed deaths and that number keeps rising,” Mr Brumby said.
“Our hearts go out to all of the families, friends and the relatives.
“The thoughts and the hopes and the prayers of all Victorians are with those families.”
Mr Walshe said he could not determine whether the victims were civilians or firefighters. He said identifications could not be carried out until at least Sunday.
The Department of Sustainability and Environment (DSE) said at least 100 homes have been destroyed as nine major blazes burnt out of control across Victoria in the worst fire conditions in the state's history.
More than 3,000 firefighters and many more residents battled major fronts at Horsham, Coleraine, Weerite, Kilmore East, Bunyip, Churchill, Dargo, Murrindindi and Redesdale in all corners of the scorched state as the searing heat in the mid 40s and high winds exceeded authorities' predictions of the worst fire conditions in the state's history.
The Kilmore fire started at 11.49am (AEDT) and quickly spread to neighbouring towns.
But with the cool change which swept across the state late Saturday afternoon came a shift in direction of the wind which then sent the fire eastwards towards Whittlesea and the sub alpine communities of Kinglake, Healesville and Warburton.
It grew alarmingly from a 4,000 hectare blaze to one covering 30,000 hectares in just a few hours.
Five hundred firefighters on 100 trucks were battling the inferno which was threatening to push even further into the town of Broadford which was warned to be on high alert on Saturday night.
Water bombing aircraft will resume operations at first light on Sunday.
Ambulance Victoria said it had airlifted a young girl with burns from Whittlesea to Royal Melbourne Hospital and had set up casualty centres at Whittlesea and Kinglake to deal with mounting injuries.
More than 3,000 firefighters and many more residents battled other major fronts at Horsham, Coleraine, Weerite, Bunyip, Churchill, Dargo, Murrindindi and Redesdale in all corners of the scorched state as the searing heat in the mid-40s and high winds exceeded authorities' dire fears.
Several areas of Gippsland in the east were on high alert as an uneasy dusk fell on Saturday night, while the Horsham fire was downgraded early in the evening.
Fifty houses were reportedly lost in the Bendigo area in the Redesdale blaze.
The cool change early Saturday evening was expected to create more volatile conditions.
"It hasn't helped the firefighters, only presented them with new fronts," a CFA spokeswoman said.
The CFA and DSE (Department of Sustainability and Environment) warned Victorians to prepare to be hit by fire late on Saturday night and to be especially prepared for ember attack.
La Trobe Valley power stations were under threat as a fire on the eastern fringes of the Strzelecki Ranges spread toward the Gippsland coast, threatening towns such as Yarram, Langsbrough and Manns Beach.
"It is pretty well every part of the state except the far northwest," CFA Deputy Chief Fire Officer John Haynes said.
"The fire weather ... was extreme and off the scale."
The Horsham fire burnt 5,700 hectares and claimed at least three homes, the town's golf club and several sheds, while the Bunyip State Park fire reached 2,400 hectares and destroyed some houses in the town of Labertouche.
Victoria Premier John Brumby said one fire threatening his parents' home in Coleraine was stopped literally on their doorstep.
"I would like to thank DSE, CFA and SES (State Emergency Services) fire fighters and volunteers who have fought tirelessly throughout the day to protect Victorian people and property," Mr Brumby said.
One man, aged in his 40s, is in critical condition after suffering burns to 50 per cent of his body when he tried to move stock in Coleraine area.
The fires came as Melbourne reached its hottest ever temperature of 46.4 degrees, while nearby Avalon recorded the state's high of 47.9.
The Ash Wednesday fires in February, 1983 claimed 47 lives in Victoria and 28 in South Australia and remain the deadliest bushfire in Australian history.
More than 100 fires which started on February 16, 1983, destroyed 2,800 homes in Victoria and burnt out 210,000 hectares, while 383 homes went up in South Australia.