A man died and four other people were missing after a fast-moving wildfire destroyed at least 46 homes in western Australia's Perth, officials said Monday.
The blaze, thought to have been started by a fallen power line in the city's wooded outskirts on Sunday, was fanned by hot, strong gusts that saw 20-metre (66-foot) flames tear through residential streets.
"It has been confirmed that 46 homes have been lost," Western Australia state's fire and emergency services department said, warning that some 30 percent of the fire zone was yet to be assessed.
State fire commissioner Wayne Gregson said four people remained "unaccounted for" Monday, with fears they had fallen "victim to the fire".
"We will follow up until we find these persons," Gregson told reporters.
"We're working very hard with police."
Earlier, the ambulance service said a man, aged 62, had died after collapsing on the roof of his house as he prepared for the oncoming blaze.
Hundreds of residents fled their homes for evacuation centres and were anxiously awaiting news Monday. Some said they had only seconds to escape.
"We obviously knew that the fire was moving pretty quickly," Stoneville resident Aaron Miles told the Australian Broadcasting Corporation.
"We just went for the important stuff -- hard drive, documents. Everything else is technically replaceable if it comes to that."
Officials said the blaze had been contained but not controlled, and warned that there was still a risk to life and property if conditions shifted.
There were 275 firefighters still battling flames which had already burnt through 650 hectares.
"If you are not at home, do not try to return as conditions in the area could be very dangerous," the fire service said.
"If you are at home, do not try to leave as conditions in the area could be very dangerous and you will not be able to return."
Perth sweltered through a heatwave over the weekend with temperatures reaching 44 degrees Celsius (111 Fahrenheit).
That heat system is now moving east across the continent, with temperatures in excess of 40 degrees forecast in Adelaide and Melbourne this week.
Hospitals and emergency services are on standby with forecasters warning of an extreme and prolonged heat event.
"The current event shows large areas of southern Australia will reach severe to extreme heatwave conditions," a weather bureau spokesman said.
Some swimming pools, shopping centres and public libraries will offer extended opening hours, and the Red Cross will make regular calls to at-risk residents, particularly the sick and elderly, to check on their welfare.
South Australia state's health department urged residents to stay indoors, wear cool clothing and drink plenty of water.
Wildfires are a common feature of Australia's December-February summer months, with a devastating firestorm in 2009 killing 173 people and razing thousands of homes in south-eastern Victoria state.
During the heatwave that preceded that disaster an additional 374 people died from heat-related causes not linked to the fires, said La Trobe University wildfires expert Jim McLennan.
"The threat to life from a period of very hot weather should not be underestimated," he said.
Unseasonably early infernos broke out in the Blue Mountains west of Sydney in October, destroying more than 200 homes and claiming two lives.
That followed an unusually dry and warm winter and record spring temperatures, prompting debate about the role of climate change.
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