A 59-year-old man remains in a serious but stable condition after his truck rolled at high-speed on the Pacific Highway north of Sydney early this afternoon.

The man was ejected from the semi-trailer and trapped beneath the cabin, his arm pinned and partially submerged in pooling water.

CareFlight’s rapid response rescue helicopter flew to Berowra shortly after 12.30pm. Heavy rain and low cloud led the helicopter to despatch the critical care medical crew at a nearby oval to meet a police car.

CareFlight’s specialist doctor and intensive care paramedic were quickly conveyed to the scene, where they assisted the man, who remained trapped for about 45 minutes.

The truck was weighed down with its load of about 20 tonnes of bitumen, with traffic blocked in each direction.

The man was extricated by NSW Fire & Rescue and emergency service crews with the assistance of a crane.

The man was taken by road ambulance to Royal North Shore Hospital under the ongoing care of CareFlight’s doctor and paramedic, along with NSW Ambulance crews.