A man is in a serious condition in Wellington Hospital after a crash just north of Kaikoura this morning.

Emergency services were called to the incident on State Highway 1 near Clarence at ten to eight.

The man in his 40s was driving a truck and trailer unit when it left the road on a moderate bend, and rolled onto its side.

He was treated by paramedics at the scene, before a Life Flight Westpac Rescue Helicopter airlifted him to hospital.