Police say this northbound Nissan Navara van - lying on its side across the highway - appeared to have crossed the centreline before slamming into an oncoming Volkswagen Polo.
A witness says two men involved in a fatal car crash appeared to be drunk at 8.20am.
The men were in a four-wheel drive Nissan Navara van which collided with a Volkswagen car in a smash on State Highway 10, a few kilometres south of Puketona Junction, about 8.20am yesterday.
A Bay of Islands woman in the Volkswagen died in Whangarei Hospital after the crash.
An angry witness said both the driver and passenger in the van appeared "extremely intoxicated".
Wine from the van had spilled onto the road and the accident scene reeked of alcohol.
A police scene examination and witnesses suggest the Nissan crossed the centreline before colliding with the south-bound Volkswagen.
The Volkswagen was crushed by the impact, leaving its 46-year-old female driver by far the most seriously injured of the three.
She died a few hours later at Whangarei Hospital.
The witness told the Northern Advocate he was angry "to see these two idiots do that to someone else".
Police are waiting for the results of blood tests  before drawing any conclusions.
But Kerikeri police Sergeant Ross Laurie said alcohol could have been a factor.
The crash occurred on a gentle bend in good driving conditions.
A scene examination and witness accounts had confirmed that the Nissan Navara was a car-width across the centre line when the vehicles collided, Mr Laurie said.
Baby gear in the car had rescuers worried at first that a young child could have been trapped in the wreckage, but a thorough search proved the woman was the sole occupant.
St John advanced paramedic Mark Going said both Northland Emergency Services Trust helicopters were sent to the crash scene, landing in a paddock beside the highway.
The woman was flown to Whangarei Hospital in a critical condition, requiring advanced life support on the way. A 49-year-old man - thought to be the driver of the Navara - suffered serious spine and chest injuries and was also airlifted to Whangarei, while a moderately injured 51-year-old man was taken by road to Bay of Islands Hospital. The crash disrupted the start of classes at nearby Oromahoe School and forced the closure of the highway for almost four hours.
Traffic was diverted via Puketona Rd and Old Bay Rd.
Volunteer firefighters from Kerikeri and Paihia had to cut the woman free from her car. They also removed the roof of the Navara, which had ended up on its side in the middle of the highway, to free one of the occupants.
The police Serious Crash Unit is investigating.