Homes lost in massive Perth bushfire

Ten homes have been lost in bushfires in metropolitan Perth, and authorities are warning it could be days before the situation is under control amid heatwave conditions.

More than 100 firefighters are battling a massive blaze in the city's northern suburbs that forced hundreds of local families to leave as embers rained down on their homes overnight.

Department of Fire and Emergency Services Commissioner Darren Klemm said it would take time to get critical infrastructure up and running after a number of power poles were damaged.

"It's worth mentioning it's going to take us a number of days to bring this fire under control," Mr Klemm said.

Sarah Kilian stayed to defend her Tapping home from the blaze that ripped through nearby market gardens and engulfed a local park after leaping a four-lane road.

"There was two massive fires coming down the road and smoke everywhere," she told AAP on Thursday.

"We haven't slept a wink."

Ms Kilian said most of her neighbours left during the night as embers descended on their homes that border semi-rural properties.

"Lucky my hubby stomped them out. It was just scary all night - absolutely chaotic," she said.

Smoke continues to rise from the fire grounds and a lone water bomber can be seen swooping down on bushland across a paddock of green vegetables.

An emergency warning remains in place for Wanneroo, Jandabup, Mariginiup, Melaleuca, Sinagra, Banksia Grove and Tapping, about 30km north of the city centre.

Some residents continue to be told it is too late to leave and they should immediately find shelter away from the fire front that is moving in a southwesterly direction.

"You are in danger and need to act immediately to survive," the Department of Fire and Emergency Services said on Thursday.

"There is a threat to lives and homes."

Chief Superintendent Metropolitan David Gill said firefighters were working to strengthen containment lines around the blaze

"In these conditions, these fires can spread so fast," he told ABC News.

He said the fire had "pulled up" as it reached urban areas and was spreading on its flanks to the north and south.

"We are expecting strong winds again today in difficult conditions with high temperatures," he said.

Western Australia is in the grip of a severe heatwave and Perth is forecast to reach 40C on Thursday, with wind gusts up to 80km/h.

More than 1000 properties in the bushfire area are without power, with reports that power poles, lines and other infrastructure have been damaged.

Multiple evacuation centres have been set up for residents and animals within the fire zone.

Local resident Bruno Rikli helped evacuate an elderly couple from their home overnight as the fire front crept within a few streets of their property.

"There was a massive plume of smoke in the night sky and a ball of embers that was glowing red," he told AAP.

"Roads were blocked but we got them out."

Mr Rikli said the couple's house survived the night without damage but the wind had started to whip up on Thursday morning, with ash falling on homes several kilometres west of the blaze.

"You can smell the smoke and it's hazy but fire crews are doing an amazing job," he said.

The fire was reported just after midday on Wednesday and 15 square kilometres of bush and grassland have been burned.