Four people are dead after a car left the road and rolled in northern NSW.

Emergency services were called shortly after 5.45am to Back Channel Road at Wardell following reports of a single vehicle crash.

Police from the Richmond district found a blue Mazda BT50 utility and four people dead. They were three men, including the driver, and a woman.

The crash investigations unit is investigating the scene and a report will be prepared for the coroner.

Roads have been closed and drivers have been asked to avoid the area.

-AAP