The remaining occupants of both vehicles were taken by ambulance to Rotorua Hospital with minor injuries. Both the Rotorua-based BayTrust Rescue helicopter and the Taupo-based Greenlea Rescue Helicopter attended.
"From initial reports the small vehicle was travelling south from Rotorua to Taupo and it appears as though it drifted across the centre line into the path of the people mover," Mr Hamilton said.
"It seems the driver may have come off the side of the road, over-corrected and crossed over. It's unknown whether it was fatigued or inattention," he said.
The Taupo Serious Crash Unit were investigating.
The road was closed for up to 40 minutes to allow the helicopter to land before one lane was re-opened to allow traffic through.
Mr Hamilton said those travelling need to be aware of the increased traffic on the roads this time of year.
"Have patience, there's so much traffic on the roads at the moment, be wary of other motorists. The main message we want to send is keep cool when driving and allow plenty of time to get to your destination."
Police also wanted to remind people if emergency vehicles have their sirens and lights flashing, by law vehicles must pull over to the side of the road and stop to allow them through.