Pedestrian critical after being hit by car on Parramatta Road at Lidcombe

A male pedestrian is fighting for his life in hospital after being hit by a car and knocked underneath a truck on a busy road in Sydney's west.

The pedestrian, believed to be aged in his 30s, was rushed to Westmead Hospital in a critical condition after he was struck on Sydney's Parramatta Road at Lidcombe at around 7.35am.

According to police the man was hit by car while crossing the road before coming to rest underneath a garbage truck in the opposite lane.

It's unclear whether the man had been hit by the garbage truck as well.

The driver of the garbage truck was taken to Concord hospital and is being treated for shock, an ambulance spokesman said.

The peak-hour accident closed all city-bound lanes as police investigate.

Motorists in the area can expect delays, said the Transport Management Centre.