Five people have died tonight in a "horrendous" crash near Te Awamutu, police say.
Waikato police confirmed the deaths, saying three occupants of one vehicle, and two occupants of the other vehicle all died at the scene.
"This is a tragic incident. To lose five lives in these circumstances is heartbreaking, and our thoughts go out to all the families affected," Waikato road policing manager Inspector Jeff Penno said.
The Serious Crash Unit was at the scene and the road was expected to be shut until at least midnight.
"There is a large scene we need to work through and our priority at the moment is understanding what has occurred to cause this tragedy.
"We are also making sure that support is provided to those who need it," Inspector Penno said.
"Emergency services are here working through it, making sure we collect all the evidence, ... and trying to establish what has happened at this horrendous crash," Penno said earlier in a video interview with Stuff.
He said evidence would be collected while still maintaining respect for those who had died.
Penno confirmed it was a head-on crash.
"This is a high-volume road and at that time of day it is quite busy but we understand the conditions to be dry and the weather was fine although it would have been getting dark," he told the New Zealand Herald.
Penno said it appeared it was not environmental factors that caused the crash.
The stretch of road where the crash happened was not deemed to be high-risk.
Once the serious crash unit had completed the collection of evidence, the bodies and the vehicles would be removed from the scene and would be treated "with the respect that they deserve".
The two vehicle crash occurred on State Highway 3 / Ōhaupō Rd just before 4.45pm.
St John said three ambulances, two rapid response vehicles and two operations managers have attended, but did not say how many patients were being treated.
Fire and Emergency said three trucks from Te Awamutu and Chartwell also responded, and one remains at the scene.
Ohaupo Road is closed between Jary Road and Ngaroto Road and motorists are asked to avoid the area.
Detours are in place and motorists have been warned delays were likely.