NSW Police says one man has died in a single-vehicle crash west of Nelligen.

Emergency services were called to the Kings Highway about 6.50am on Tuesday, March 15, following reports a tipper truck had crashed east of Bolaro Road.

"Initial inquiries suggest the tipper truck was travelling west when it veered off the road and struck a steel railing before flipping and hitting a tree, about 300m east of Old Bolaro Road," a NSW Police spokesperson said.

"The driver - a man believed to be aged in his 30s - was trapped before being released, but despite efforts, he died at the scene. He is yet to be formally identified.

"Officers attached to South Coast Police District have commenced an investigation into the circumstances surrounding the crash."

Police are now asking any witnesses or anyone who may have dashcam footage of the crash to contact Batemans Bay Police on 4472 0099 or Crime Stoppers on 1800 333 000.

The Kings Highway has re-opened, however a contra flow has been put in place and motorists are being encouraged to find an alternate route.

ORIGINAL STORY (8.33am)

The Kings Highway is closed to heavy vehicles in both directions west of Nelligen due to a truck crash near Bolaro Road just after 7am on Tuesday, March 15.

A spokesperson from the Transport Management Centre said heavy vehicles should consider postponing their trips or finding alternate routes.

"Stop/slow conditions are in place on the Kings Highway at Nelligen due to a truck crash east of Bolaro Road," they said.

"Heavy vehicles are unable to pass the scene and are urged to delay their trip or use an alternative route.

"Traffic is heavy in both directions.

Motorists are urged to allow extra travel time and follow the directions of emergency services on scene."

This story will be updated as more details come to hand.