Kaikohe fire chief Bill Hutchinson said it was not clear what had caused the vehicle, a compact SUV similar to a Nissan Terrano, to leave the road.
Volunteer firefighters had to free the critically injured driver using hydraulic cutting equipment.
St John medics performed life support for two hours but were unable to save him. The rescue helicopter landed nearby but the driver died before he could be transported to hospital.
Sergeant Tai Patrick, of Northland police, said the vehicle had gone into a drain while rounding a moderate right-hand bend.
It had dug into a bank, hit a tree stump and spun around.
The driver, who was unrestrained, had been thrown into a pillar behind the driver's door and suffered critical head injuries.
The man's name has yet to be released. He was believed to be 66 years old and from the Kaikohe area.
No other vehicles were involved and the driver was the sole occupant.
The crash brings the Northland road toll to 13 so far this year, according to Ministry of Transport figures.
It was the fourth road fatality in Northland since the Covid-19 lockdown started at 11.59pm on March 25. Of those three are believed to have involved non-essential travel.
A 34-year-old man died in a single-vehicle crash on Paparoa Rd, south of Whangarei, on March 26.
A 66-year-old man died on April 6 when his vehicle veered off Brooks Rd, Waipu, into a tree. That crash, however, may have been caused by a medical event. Police said the driver was engaged in essential travel.
On April 19 Nga Roimata Beattie-Rihari, 18, died when the parked car she was sitting in was hit by a vehicle being driven on the wrong side of Mason Ave, Moerewa. She was six months pregnant.
Ioakimi Sale, 43, has been charged with driving with excess breath alcohol causing death and other offences in relation to the Moerewa crash. He is being held in custody pending his next court appearance on May 18.
