Four-car crash on Mt Ousley

9.30am: The accident site has been cleared and all lanes have been reopened on the M1 Princes Motorway after an earlier accident.

Earlier: Southbound traffic coming down Mt Ousley is banking up following a four-car accident.

The accident happened around 8.15am in the southbound lanes of the M1 Princes Motorway, near the New Mt Pleasant Road overpass.

It is understood the four-car accident has closed the left lane of the road.

At this stage traffic is heavy, and starting to stretch back to the top of Mt Ousley.