The driver of a four-wheel-drive vehicle could face charges over a collision with another vehicle in the Waikato on Monday which seriously injured two young boys.
But police say an investigation into the crash is complex and it could be several weeks before a decision was made on laying charges.
The accident, on State Highway 27 at Patetonga, happened when an Auckland family heading home in their Toyota Hilux and a Kia Cerato collided about 5.40am on Monday.
Two boys aged 4 and 6, neither of whom was in a car seat, were in the back of the Toyota and suffered serious injuries.
The older boy suffered arm injuries and possible internal injuries and was flown with his father to the Starship children's hospital in the Westpac Waikato Air Ambulance.