Bushfires that destroyed at least 59 Perth homes and forced hundreds of people to flee for their lives continued to burn out of control last night.

Fire authorities said a huge blaze at Roleystone, on Perth's southeastern fringe, would burn for days, while other fires threatened more suburbs and police warned that anyone trying to break through cordons to reach their homes would be arrested.

State Premier Colin Barnett yesterday declared Roleystone a disaster area.

No deaths had been reported last night, but more than a dozen people had been treated in hospital for smoke inhalation, and a firefighter was in a stable condition after a vehicle accident.

State Emergency Services Minister Rob Johnson warned that the number of houses destroyed could rise.

"We don't know by how many," he said. "Until the fire is fully extinguished we won't know the full extent."

The Roleystone fire also burned into the neighbouring suburb of Kelmscott, and fire crews were battling other outbreaks at Red Hill, at Jarradale, 60km south of Perth, and Brigadoon, north of the city.

Another major blaze threatened vineyards, farms and homes near the Swan Valley community of Chittering.

Late yesterday Fire and Emergency Services Authority state co-ordinator Mal Cronstedt told reporters the Roleystone fire had largely been contained by a "herculean effort", but remained out of control.

"We expect that the effort in Roleystone will go on for many days yet," he said.

More than 100 firefighters were last night still fighting the blaze in hilly, dangerous country, after two days of strong winds and temperatures in the mid to high 30s.

Triggered on Sunday afternoon by sparks from an angle-grinder, the fire torched nearby dry grass and, driven by winds gusting up to 100km/h, raged into a suburb that was given almost no warning to flee.

At 1.30pm on Sunday fire authorities gave residents 20 minutes to leave.

"There is a threat to lives and homes. You are in danger and need to act immediately to survive," their broadcast alarm said.

People in both Roleystone and Kelmscott ran for their lives.

"It was so quick," Talia Tucci, 16, told the West Australian's website thewest.com.au. "I went outside and all I could see was black smoke everywhere.

"We could see our next-door neighbour hosing everything down but his house just burned and then it came up to the back of our house and we had no time to get anything, it just came up too fast."

The website said that as the Tuccis fled with only a handful of possessions, firefighters were forced to jump off the balcony of the house to escape the flames.

Another Kelmscott resident, Sean Roberts, slung his partly paralysed brother over his shoulder and ran from his parents' burning house as flames swept through their property yesterday.

"My dad came down and told me there was a fire, by the time we got up to his place I just had time to throw my brother over my shoulder," Roberts told thewest.com.au. "We went to go out the front door, the cars were on fire, the front veranda was on fire.

"I tried to go out another door, couldn't get out that one, went out another door and just ran with him down to the back of the property down near Stony Brook Creek.

"It was scary. It was just a matter of grabbing him out of his bed and running."

Elsewhere, Brooke Weir, 20, said flames had reached a neighbour's property and had taken hold of the house in the time it took the owner to pack her cat and belongings into her car.

Hundreds of people fled to evacuation centres, many returning to roadblocks later to watch their suburbs burn, hoping to hear the fate of their homes late yesterday at a planned community meeting.

Barnett said the state Government would provide immediate financial aid for fire victims, a Lord Mayor's relief fund has been set up, and donations of bedding and clothing were already arriving at collection points yesterday.

Meanwhile, flooding has eased across Melbourne and Victoria after the weekend's deluge, AAP reported.

A man has died after falling while repairing his leaking roof in Melbourne's south-eastern suburbs and a 26-year-old English tourist remains in a critical condition in hospital after a large gum tree fell on her tent at a caravan park in Doncaster during torrential rain.

A large number of roads remain closed throughout Melbourne and across the state, including all roads to and from Kerang in northern Victoria.