Fences and sheds have been singed in a bushfire which continues to threaten homes east of Perth.

Residents in Red Hill, Millendon, Herne Hill and Baskerville in the City of Swan, about 20km from the CBD, have been told they are in danger and need to act to survive.

The fire started near Toodyay Road in Gidgegannup about 12.30pm on Tuesday.

So far some 650 hectares have been burned as the West Australian Department of Fire and Emergency Services tries to manage the blaze.

Acting Superintendent Paul Postma said air support would be needed to battle the blaze.

“They’ll be doing a lot of retardant drops through the bush area, trying to contain the fire and preparing for the extreme winds that we have got forecast today,” he said on Wednesday morning.

“We don’t have any reports of homes lost but we do have reports of damage to two sheds and a number of (fences) and minor property damage.”

Postma said he still had concerns about the fire around the rural properties as conditions worsen on Wednesday.

Some 120 firefighters, including volunteers, are involved.

The department said residents must leave if the way is clear, or prepare to shelter at home.

– AAP