Eight people are confirmed dead in the horror crash in Atiamuri, north of Taupō, on Sunday after a SUV and a van collided.
Police say the driver of the SUV and the driver and six passengers in the van were killed in the crash, which left a young boy with critical injuries.
"The disaster victim identification team (DVI) have been called in to assist with the investigation," a police spokesperson says.
"At least one person suffering critical injuries was air-lifted to hospital this morning."
The serious crash unit has been notified and the road has been closed for an extended period for the scene to be examined.
Footage shows two vehicles crunched together in the aftermath of the crash. It appears that one vehicle slid over the yellow lines while travelling around a corner and was hit side-on by another vehicle.
Motorists are warned to plan their journey to avoid SH1 between Taupō and Atiamuri if possible.
Taupo's mayor, David Trewavas, says the crash is "devastating" and he's promised to offer support to all those impacted by the horror crash.
"All the services will be available," he told Newshub.
"It's not only the families involved in the actual event, but it's the emergency services, the responders at the scene, the neighbours up the road, the farmers in the district, all that sort of thing. It just affects everyone and they never get over it."