A 44-year-old man was taken to Dunedin Hospital after his Mazda car and a truck and trailer unit collided head on about 10.30am.
Southern District Command Centre deployment co-ordinator Senior Sergeant Dave Scott said the car driver was trapped in the vehicle and had to be cut from the vehicle by Fire Service staff.
He was taken to Dunedin Hospital in a serious condition.
A hospital spokeswoman said the man was in a stable condition in the general ward last night. He was conscious and alert, she said.
The truck driver was uninjured. The police serious crash unit is investigating.