A multi-vehicle crash has caused heavy traffic delays on a major motorway in Sydney.

Two of the three citybound lanes were closed on the M5 after Henry Lawson Dr at Milperra due to a collision between three cars on Monday morning.

No injuries have been reported, NSW Police told 7NEWS.com.au

All citybound lanes are now clear however there are still extensive delays.

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“Allow plenty of extra travel time,” Transport for NSW said.