Firefighters worked throughout the night to control a fierce bushfire, which razed 68 homes in the Perth Hills.

WA Fire and Emergency Services Authority (FESA) spokesman Allen Gale confirmed today that the fire had destroyed 68 homes, some of which may be units within larger buildings.

Earlier, FESA said firefighters had consolidated fire breaks during the night to contain and control the fire, which had burnt about 440 hectares since it started on Sunday.

But FESA warned residents in the southwest of Roleystone and southeast of Kelmscott to remain vigilant because of strong easterly winds in the area.

FESA's Bruce Telfer said firefighters had consolidated containment lines around the fire.

"Firefighters have worked really hard throughout the night consolidating the fire breaks that were established around the fire and also mopping up to make sure that aerial fuels are accounted for, as well as the ground mop-up to make sure that no embers can get over the fireline we've established," he told Fairfax Radio Network.

At a public meeting in nearby Armadale yesterday, evacuees were told by authorities whether their houses had been destroyed, damaged or spared.

FESA incident controller Gary Kennedy told thousands of people at the community meeting in Armadale that ember attack was still a real threat to properties and the fire zone remained dangerous because of falling power poles and trees.

Firefighters managed to save a number of homes, sheds and fences, FESA said.

The fire was accidentally sparked by a man, believed to be a police officer, using an angle grinder.

A total fire ban was in place at the time.

Police have spoken to the man but no charges have been laid at this stage.

The West Australian newspaper reported the man was a police officer who was using the grinder on a trailer at the front of his Brookton Highway home.

The paper said arson squad officers had seized the trailer.

He could be charged with carrying out an act in the open air that causes a fire and face a maximum penalty of A$25,000 ($32,825) or 12 months' jail, the newspaper said.

There have been no deaths in the fire but a firefighter was in a stable condition in hospital after being hit by a vehicle; several people were also treated in hospital for smoke inhalation.

On Monday afternoon firefighters had another dangerous fire to the north in the City of Swan mostly under control.

An emergency warning was downgraded to a "watch and act" advisory and then further to a bushfire advice on Monday night.

That fire, which started on Saturday, has burnt 1170 hectares but no homes had been destroyed or damaged.

A total fire ban has been declared for Perth, the Perth Hills and surrounding areas.