Car causes crash after driving wrong way

A truck driver was trapped in his cabin with serious leg injuries in an accident caused by a hatchback driving towards him on the wrong side of the road in Sydney's south.

Two trucks were travelling south on General Holmes Drive in Mascot late on Wednesday when a small silver hatchback drove towards them on the wrong side of the road as they approached the merge with Southern Cross Drive, police said.

The first truck braked and took evasive action to avoid a crash, causing the second truck to collide into the rear of the lead truck, trapping the 53-year-old driver.

The hatchback drove off with its lights off, while the injured driver was taken to St George Hospital.

Police would like to speak to anyone who witnessed the accident.