A driver had to be cut out of his car after he smashed into a lamp post on Lake Rd.
He was taken to Rotorua Hospital in a critical condition after the single-car crash, which happened about 5.30pm, according to a St John ambulance spokeswoman.
A police media spokeswoman said police received a call saying a car had lost control at a roundabout and hit a lamp post in the middle of the road.
Bay of Plenty police district command centre Senior Sergeant Karl Konlechner confirmed the car had "failed to negotiate the roundabout" before hitting the pole.
Rotorua Fire Brigade senior station officer Colin Rolfe said when his crew arrived at the crash scene the driver was unconscious.
Firefighters used hydraulic equipment to cut the roof off the car, giving ambulance staff more room to work, he said.
They continued cutting the car and managed to free the man.
"When we got him out he was conscious," Mr Rolfe said.
Mr Rolfe said he understood there were two passengers in the car but they were out of the car before the crew arrived.
No other injuries were reported.
Lake Rd was closed in both directions, with diversions in place, for about two hours.
Mr Konlechner said the Serious Crash Unit was investigating.
A Rotorua Hospital duty manager said the man was still in the emergency department and no update on his condition was available.