Driver freed from truck wreckage as crash sparks traffic chaos on Sydney motorway

Traffic on Sydney's M1 Pacific Motorway is starting to ease after significant delays this morning after two trucks collided, leaving one driver trapped.

Authorities rushed to the major motorway just past Jolls Bridge on the Hawkesbury River, following reports a large truck had run into the back of another just before 10am.

One driver was trapped inside one of the trucks, while the other driver was uninjured.

A doctor was airlifted to the site by CareFlight to assess the injured driver, who is believed to be in his mid-40s. The second driver was not injured.

He was freed from the cabin of his truck and airlifted to hospital.

All northbound traffic was held while the helicopter departs.

There are still significant delays and motorists are urged to take caution if travelling on the motorway, with earlier traffic queued up to 11 kilometres as emergency services attended the accident.

All northbound lanes of the M1 are now open and the crash site has been cleared.