One lane of State Highway 1 has reopened following a two-vehicle crash near Hampden this afternoon.
A Hato Hone St John spokesman said one person in critical condition was flown to hospital following the crash near Moeraki Boulders Rd, which was reported at about 4.20pm.
Another patient in moderate condition was taken by road to Oamaru.
The helicopter, an ambulance, a rapid response vehicle and a Primary Response doctor responded to the incident, he said.
A police spokesman said the Serious Crash Unit had been notified.
Motorists were told to take extra care and expect possible delays.
A Fire and Emergency NZ spokeswoman said crews had cut free one person who was trapped in a vehicle.
Crews from Hampden, Palmerston and Weston had responded to the crash.
