Police said the immediate concern was for the families involved, and the investigation into the cause of the crash was continuing.
It was wet at the time, and police said this would be considered as part of the investigation. The road was closed for about an hour, before being opened to one lane. It was reopened completely at about 3.45pm.
Whangarei Police Senior Sergeant Darren Sullivan said police were urging the public to drive to the conditions.
Heavy rain forecast to hit Northland from now into next week would make the roads more dangerous, he said.
"We're urging drivers to plan their trips and drive to the conditions."
A storm predicted to dump up to 100mm of rain on Northland yesterday failed to materialise by edition time. There was plenty of rain and wind around the region, but no reports of flooding or damage.
The MetService says there will be more rain today, though as of edition time it said there was low risk of it sparking a heavy rain warning. The forecast is for rain in Northland into next week, with the possibility of some fine spells on Sunday.
Yesterday's crash comes a day after Northland's first fatal crash of 2018 and a spate of crashes across the region.
A woman was killed when she struck a power pole and flipped on Mangakahia Rd on Wednesday. The same day a ute and a motorcycle collided on Kerikeri Rd. The rider suffered head injuries and a possible broken leg.
On Tuesday a ute collided with a truck and rolled several times after a car passed the ute at speed and kicked a large cloud of dust, leaving drivers unable to see.
Also on Tuesday, a car hit a power pole on Pipiwai Rd, leaving the driver with moderate injuries.
