A truck driver in his 30s has been rushed to hospital with serious head injuries after a collision closed the M1 north of Sydney.

A driver suffered “severe injuries and was trapped” inside a truck following a collision with a car on the motorway near Calga shortly before 20 am.

The truck rolled onto its side.

NSW Ambulance paramedics attended to the man at the scene before he was airlifted to Royal North Shore Hospital, where his condition was reported as serious but stable.

The driver of the car suffered minor injuries.

One northbound lane of the M1 has now reopened at Mooney Mooney but traffic is heavy according to LiveTraffic.

Motorists can consider using Peats Ridge Road to Somersby or the Old Pacific Highway to Kariong instead.