A fast-moving wildfire destroyed at least 27 homes in western Australia's Perth, officials said, with one man dying as he prepared for the approaching inferno.

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 flames tear through residential streets.

"It has been confirmed that 27 homes have been lost at this stage, but this number is expected to increase as damage assessments continue throughout the day," Western Australia state's fire and emergency services department said on Monday.

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.

"St John's Ambulance responded to the incident but was unable to access the roof," it said.

Flames prevented paramedics from reaching the man who collapsed on the roof of his home in suburban Hovea on Perth's eastern fringe.

"Despite assistance from the Department of Fire and Emergency Services (DFES) in getting onto the roof, the man passed away at the scene."

Hundreds of residents fled their homes for evacuation centres and were anxiously awaiting news on 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.

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 the flames.

The state fire service said in a statement on Monday that the number of homes being destroyed was expected to rise as damage assessments continued.

They also warned people to stay away from their homes as “the conditions in the area could be very dangerous.”

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 southeastern Victoria state.

Unseasonably early infernos broke out in the Blue Mountains west of Sydney in October, destroying more than 200 homes and claiming two lives.

The heat is now expected to move east across the continent, with temperatures in excess of 40 degrees forecast in Adelaide and Melbourne later this week.

Source: Agencies