A multi-car crash has caused heavy traffic to bank up on a major road in Western Sydney.

The cars collided just before 8.30am on Friday at the intersection of Marsden Rd and Stewart Ave in Ermington.

NSW Ambulance attended the scene.

Traffic was heavy as lanes were closed on Marsden Rd, however, they have since reopened.

Motorists are urged to exercise caution as traffic returns to normal.

Source Credit: 7 News