Multiple crashes across Perth have brought the morning commute to a crawl, with motorists facing lengthy delays on some of the city’s busiest roads.

The most serious congestion is on Mitchell Freeway southbound at Greenwood, where a crash before Warwick Road has reduced traffic to a single lane.

An ambulance is at the scene and traffic is heavy on the approach, with drivers urged to take care.

A crash on Leach Highway westbound just after Kwinana Freeway at Bateman has closed the right lane.

Incident response crews and towing services are at the scene as traffic remains heavy on approach.

Motorists are urged to allow extra travel time, slow down near the incidents and follow directions from emergency crews.

On Mitchell Freeway, a tarp has been reported on the northbound carriageway before Hodges Drive at Heathridge.

Traffic is still moving through the area but motorists are being told to drive with caution.

Earlier, a crash on Roe Highway eastbound before Spencer Road at Langford blocked the right lane.

Traffic has backed up past Willeri Drive, with drivers urged to merge carefully.

Another crash on Leach Highway eastbound at Centenary Avenue in Wilson has blocked the left-turn lane, causing delays back to Corinthian Road East.