A 29-year-old male, possibly a foreign tourist, has been airlifted to a Sydney hospital in a serious condition after being involved in a skateboarding accident on Barrengarry Mountain.

Around 11am emergency services were called to the last hairpin bend heading west on Barrengarry Mountain where the skateboarder had collided with a caravan, which was being towed at low speed.

The man suffered serious chest and abdominal injuries.

He was treated at the scene and taken by ambulance to a cleared location about three kilometres away where the Ambulance Rescue helicopter from Albion Park had landed.

He was airlifted to St George Hospital in a serious condition.

The roadway was closed for a short period of time but is now reopened to traffic.

Police Crash Investigation officers are investigating the accident.