The outcome of the investigation into the cause might not be known for months, with police saying the process would be lengthy.
Police were last night still not in a position to release the names of the victims.
But as the investigation enters its second day, they have vowed to keep a close eye on Waikato roads - which were also the scene of death last week - over the upcoming long weekend.
“We do not understand why it happened,” Penno told media.
All of the occupants of the vehicles died at the scene.
The Serious Crash Unit had already conducted a “meticulous” scene examination but the crash investigation is “likely to take several months”, with Penno noting the scene was not in a state for investigators to know whether those in the vehicles were wearing seatbelts.
“The findings from that examination and forensic evidence obtained will feed into a crash investigation.
“We are now moving on to the next stage, which includes examining the vehicles involved to tell us more about what occurred.”
The section of the road isn’t known for being dangerous and early indications are that it was not a factor in the crash, Penno said.
“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, albeit getting slowly darker.”
All family members of those who died have been contacted.
Police were well down the path of identifying the victims but were not in a position to release details, Penno said.
Police would also be looking at whether either driver was impaired.
“Impairment is always something we look at, to ensure all drivers are sober, not just alcohol but illegal and legal drugs and that is certainly a focus of this accident.”
“A very confronting scene”
Penno said it was particularly hard on the young emergency personnel who attended the crash scene and wanted to acknowledge those who responded, including members of the public first on the scene.
“This was a very confronting scene, even for our experienced emergency services staff.
Including the fatalities from yesterday’s crash, the ministry’s provisional data shows 26 people have died on Waikato roads this year. Last year’s total provisional road toll for the region was 67.
In 2022 and 2023, Waikato region had the highest road toll in the country.
Jaime Lyth is a multimedia journalist for the New Zealand Herald, focusing on crime and breaking news. She began working under the NZ Herald masthead in 2021, as a reporter for the Northern Advocate in Whangārei.
Maryana Garcia is a Hamilton-based multimedia reporter covering breaking news in Waikato. She previously wrote for the Rotorua Daily Post and Bay of Plenty Times.