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.
The police officer said the man was possibly not wearing a seatbelt.
Waipu Volunteer Fire Brigade chief fire officer Trevor Vaile said his crew were called to help. After conducting a search of the scene, they helped to control traffic.
The road remained open while emergency services attended the scene but was controlled by a stop-go system.
The name of the deceased man has not yet been released.
This fatality brings the Northland road toll to 22 for the year to date. The total for all of 2016 was 27.
Not wearing a seatbelt has been a factor in at least nine of the 21 previous deaths on Northland roads this year.
The serious crash investigation is ongoing.