Fire crews had to cut four foreigners - three of them dead - from a car after it crashed into a truck on the Desert Road.
The road was partially closed for much of today following the accident, in which the sedan crossed the centre line and collided with the truck, about 7.30am.
The crash occurred between Waiouru and Turangi, north of the Rangipo Intake Road.
The driver survived but was in a critical condition in Waikato Hospital's Intensive Care Unit.
Senior Sergeant Fane Troy told Checkpoint with John Campbell the driver had lost control, and crossed onto the wrong side of the road.
"From the initial investigation at the scene by crash analysts, the north-bound vehicle has crossed the centre line and collided with the heavy motor vehicle that was travelling south.
"The Fire Service had to use cutting equipment to get the driver out, and also to get the other three deceased occupants out."
All of those in the car were aged in their mid-20s but he was not sure how they knew each other.
Police were liaising with embassies in New Zealand to identify them, and trying to contact next of kin. They expected to be able to release the victims' names tomorrow, he said.
The Serious Crash Unit was investigating.
The New Zealand Transport Agency had urged caution on the road because of snow and ice, and MetService had forecast snow showers above 900m until about midday.
In addition to the fatal crash, there were several minor crashes in the region this morning and damage to vehicles, police said.
They warned driving conditions could remain hazardous for the rest of the day.