A spokesperson from the helicopter said in a statement fire crews cut the driver of the truck from his vehicle, before he was flown to hospital.
"He had suffered multi-trauma injuries and fractured legs. He was treated enroute by an intensive care paramedic and delivered to waiting medical teams at Nelson hospital."
After dropping off the driver of the truck, the helicopter was refuelled but unable to return to Murchison due to fog.
"This required the ambulance service to head towards Nelson until a suitable landing site was found," the spokesperson said.
The ambulance vehicles met up with the helicopter on a roadside layby, where the passenger from the truck and a traveller sitting at the front of the campervan were loaded onto stretchers.
They had suffered leg and other trauma injuries, the spokesperson said.
A third patient with minor injuries was able to be seated in the helicopter.
All three were then flown to Nelson Hospital for further treatment.
Police are currently investigating the collision.
