A 32-year-old man has died after being thrown from his vehicle when it rolled near Waipu.
The crash happened just after 3.30am on Saturday at the intersection of State Highway 1 and Brooks Rd.
Serious crash investigator Senior Constable Warren Bunn said the vehicle was travelling north when it crossed the centre line to the other side of the road.
He said it then swerved before rolling.
Mr Bunn said the driver, the only person in the vehicle, was thrown out of it.