A serious crash closed a major Perth road during peak-hour traffic on Thursday.

Police shut Scarborough Beach Road southbound between Hutton Street and Drake Street just before 9am as emergency services rushed to the collision involving three vehicles.

St John ambulance attended the scene and police officers directed traffic at the intersection.

The crash caused heavy congestion in the area and motorists were told to seek an alternate route.

The road was re-opened about 30 minutes after the crash, with Main Roads confirming traffic was flowing normally.

The crash was just one of many incidents causing chaos on Perth roads on Thursday morning, with five intersections also experiencing traffic light blackouts just after 9.30am.

Intersections affected are:

• Karrinyup Road and North Beach Road
• Stephenson Avenue, Howe Street and Flax Way
• Stephenson Avenue and Oswald Street
• Ellen Stirling Boulevard and Oswald Street
• Ellen Stirling Boulevard and Sunray Drive

Main Roads said anyone driving through those intersections needs to slow down and give way to their right.

Further east, emergency road works forced shut Reid Highway westbound between West Swan Road and Drumpellier Drive in Bennett Springs.

The left lane has been closed for asphalting works and the speed has been reduced to 40km/hr.