None of the students involved in a minivan crash near Cambridge were wearing seatbelts, police say.
The van from Maori immersion school Te Kura O Te Kaokaoroa O Patetere school in Putaruru left the road in wet weather at Maungatautiri on its way back from a funeral on Wednesday afternoon.
Four students were hospitalised for minor injuries, but later discharged.
The 36-year-old driver, a teacher at the school, suffered serious leg injuries and is recovering in Waikato Hospital on Thursday following surgery. He is in a comfortable condition.
Waikato road policing manager Inspector Leo Tooman says it is the responsibility of any driver to make sure that passengers are properly restrained.
"There were seatbelts available for the children in the van, but I understand that none of them were being restrained in the vehicle.
"So if we had the vehicle actually roll, then it potentially could have been very, very serious. Fortunately, this didn't happen, so we're quite thankful for that."
Mr Tooman says it is possible the driver could be charged in relation to the crash.
Principal Keith Silveira says two counsellors from the Ministry of Education are at the school meeting with staff, parents and students.