A breakdown on a busy stretch of Canning Highway is causing traffic headaches for commuters heading home on Thursday as peak hour hits.

The breakdown was located on the Highway westbound at the intersection with Kwinana Freeway in Como.

It was reported by Main Roads at 4.08pm.

The left lane of the Highway was partially blocked by the vehicle.

The breakdown has since been cleared, but traffic remains slow on approach to the site.

Main Roads has urged motorists planning to travel in the area to drive with caution.

A reported crash on Roe Highway also caused major congestion earlier in the afternoon.

The crash was located on the Highway eastbound before Orrong Road in Beckenham.

Traffic was backed up from the site to Nicholson Road.

The crash has since been cleared, but traffic remains slow on approach.