Western Power crews attempting to restore power to 44000 homes ...

Wet weather mixed with hot temperatures has triggered widespread power outages across Perth, with more than 40,000 homes and businesses left without electricity during the Monday public holiday.

Western Power said it is responding to about 70 pole top fires, which have cut power to about 44,000 properties, with the worst affected areas being in the city's north.

The utility said it received initial reports of pole damage in Greenwood, Padbury and Kingsley, but outages have now been reported as far south as Mandurah.

Main Roads is reporting widespread traffic light blackouts.

It's a public holiday in WA, with many cafes and small businesses without backup power having to shut.

Western Power spokesperson Zane Christmas said some residents may not have power restored until tomorrow.

He told ABC Radio Perth weather conditions had contributed to the issue.

"Really light, drizzly weather after long hot spells is really difficult for us to manage," he said.

"Really soft, gentle rain mixes with the pollution on the insulators."

In a statement to its website, Western Power said there were "elevated faults" across the network.

"Due to a significant number of asset replacements required, some customers may experience extended outages."

Power is expected to be restored to some areas by 5pm, but Mr Christmas said the blackout may not be completely resolved until tomorrow.

"When you have these pole fire issues it does damage the poles and often it leads to a longer outage period," he said.

"So to be honest, there will be some customers that will be off overnight."

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