Crash investigators are trying to piece together the circumstances leading up to a fatal crash at Charlestown overnight.

Police have been told a car was travelling north on the Pacific Highway just before 9.30pm on Thursday when it left the road and crashed into a power pole.

The driver, a 47-year-old man from Cardiff, who was the only person in the car, died at the scene.

The northbound lanes of the highway between Charlestown Road and Ocean View Parade were closed while officers set up a crime scene.

Traffic is now back to normal.

Police car