A breakdown on Kwinana Freeway southbound blocked a lane on the major Perth road, causing traffic headaches for motorists heading home on Saturday evening.

The breakdown was located on the Freeway after Roe Highway in Jandakot, and was reported by Main Roads at 5.22pm.

The left lane was closed by Incident Response, causing slow traffic leading up to the site.

Main Roads has advised motorists to proceed with caution.

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