Prime Minister Julia Gillard warned Australians of high bushfire risks in coming days, highlighting global climate warming as the probable cause.
"We do know over time that as a result of climate change we are going to see more extreme weather events and conditions."
She urged residents in vulnerable bush areas to decide in advance whether to attempt to save their homes, if fire strikes, or opt to evacuate.
"This is the time to be vigilant," Gillard said.
The prime minister spoke while touring Tasmania where survivors described nearly fatal incidents as wildfires engulfed their settlements, destroying 90 homes, on Friday and Saturday.
Tasmanian police said Monday no fatalities had actually been established but they were still trying to account for more than 100 persons reported missing.
Sydney facing 'awful' risk
Sydney, the major city of Australia's most populous state New South Wales (NSW), is forecast to reach 43 degrees Celsius (109 Fahrenheit) on Tuesday, which would be the third hottest day recorded in the city for 150 years.
Ninety bushfires, mostly sparked by weekend lightning storms, are already ablaze, mainly south of Sydney and in forested federal territory around Canberra, Australia's inland capital. Twenty of these are rated as out of control. Thousands of firefighters and about 70 aircraft have been put on standby.
NSW rural fire service commissioner Shane Fitzsimmons warned residents to prepare for "awful conditions," with humidity at only 10 percent and winds gusting over 70 kilometers per hour (43 miles per hour).
Victoria's 'Black Saturday' remembered
Similar conditions are forecast in the southern neighboring state of Victoria, where a firestorm in 2009 known as Black Saturday killed 173 people.
Some 13 million of Australia's 23 million population live in New South Wales and Victoria. Bushfires are also raging in South Australia and North Territory.
Western Australia, where the heatwave began just after Christmas, is already experiencing its worst scorcher in more than 80 years.
Experts say a wet, cool period of weather that followed a continental drought in 2010 went on to boost foliage growth and left fresh tinder for potential bushfires in the current hot, dry conditions.
Analysts say Australia's vital wheat exports are largely secure because the vast majority of the past winter's crop has already been harvested.
But other pending crops such as sunflower seeds and sorghum could still be impacted by bushfires, "particularly in northern New South Wales," said Andrew Woodhouse, a grains analyst at Advance Trading Australia.
ipj/rc (AFP, Reuter)