The head of Northland road policing, Inspector Anne-Marie Fitchett, said the crash was still under investigation but early indications were that the deceased was not wearing a seatbelt.
She said buckling up made a huge difference.
"If the worst happens it gives you a fighting chance," she said.
If the cause of death is confirmed, it will be just one of many crashes in Northland in recent years in which failing to wear a seatbelt was the deciding factor.
Last month a 17-year-old man from Kaitaia died when a vehicle rolled on Paparore Rd north of Kaitaia. The other occupants suffered fractures and other injuries but survived.
It is believed the deceased was thrown out of the sunroof as the car rolled.
Saturday's crash brings the number of deaths so far this year in Northland to 12 with seven of those in April alone.
At the same time last year 14 people had died on Northland roads.
