An 81-year-old man was driving a Volkswagen, which was turning, heading to Wanaka.
The man and his 54-year-old female passenger were trapped in the vehicle after it landed against a Transit sign, Snr Sgt Brown said.
The Cromwell Volunteer Fire Brigade assisted.
The driver of the Volkswagen failed to see a Toyota Camry travelling from Wanaka to Queenstown.
The Toyota's 21-year-old female driver and her 34-year-old male passenger were uninjured, as was the Volkswagen passenger.
The 81-year-old man was taken to Dunstan Hospital for assessment.