WA bushfire downgraded and rain expected

Hopes are high that forecast weekend rain will help firefighters get on top of the week-long blaze as a tropical low tracks towards the southwest.

"This is a great outcome and it gives those residents of those terribly affected areas, particularly around Tilden Park, access back into those areas from 4pm this afternoon," DFES Commissioner Darren Klemm said on Saturday.

The blaze has destroyed at least 86 homes and has burned almost 11,000 hectares in total.

The region is still on high alert with strong wind gusts of up to 90 km/h expected on Saturday afternoon.

"People who go into the fire-affected area with a permit really need to be mindful of the affect of that wind on trees and branches and the like, that may have been weakened by the fire," Commissioner Klemm said.

The downgrading from an emergency warning to a watch and act alert occurred on Saturday just after 10am AWST. It applies to Avon Valley National Park, Brigadoon, Bullsbrook, Gidgegannup, Upper Swan and Walyunga National Park.

"We're expecting light rain to commence early this afternoon but the heavier rain that will really help us with the fire is not going to occur until later on this evening and into tomorrow," Commissioner Klemm said.

He assured those who have lost their homes that DFES would continue to support them in recovery.

"I really want to stress that those homeowners that have lost their homes - we're here for the long haul," he said.

Some roads have reopened while Toodyay Road will remain closed for some time.

Firefighters have worked overtime to clear damage from seriously affected areas, including fallen powerlines, while also dealing with flare-ups on the northern flank of the bushfire and re-establishing containment lines.

Western Power says some 465 homes remain without power, with repairs to damaged electricity networks potentially continuing for weeks.

Australian Associated Press