The Waikato Westpac Rescue Helicopter flew the man to Waikato Hospital.
He sustained "multiple injuries" of a "time-critical nature", a rescue helicopter spokeswoman said.
A critically injured person had to be cut from their vehicle by firefighters after a car collided with a truck in Waihi about 1.50pm.
Emergency vehicles and a helicopter were called to the scene on Martin Rd. The person was airlifted to hospital.
The Serious Crash Unit and Commercial Vehicle Investigation Unit were investigating the crash.
Seven people were hurt in a three-car crash on State Highway 1 in South Waikato, about 2.15pm.
Two people, one with serious injuries and another in a moderate condition, were taken to hospital by ambulance, a St John ambulance spokeswoman said. Five others had minor injuries.
Emergency services were at the scene about 2.45, a police spokeswoman said.
A Fire Service spokeswoman said two people were trapped and cutting gear was used to get them out.
The crash happened near Karapiro, about 1km west of the State Highway 29 turnoff to Tauranga.
The road was closed, but no diversions were in place. Police asked motorists to drive "with patience".
A 22-year-old man was in a serious condition when he was flown to Waikato Hospital after his ute hit a power pole near Reporoa in the Bay of Plenty, about 8.30am.
He had multiple injuries.
The BayTrust Rescue Helicopter met emergency services at the scene on Plateau Rd.
Pilot Ben Fry said the chopper was used due to the distance and "time-critical nature of the injuries".
A hospital spokeswoman said the man was still serious, but stable, in the High Dependency Unit.
