One lane of the highway was closed for close to an hour as a result of the crash at the turnoff to Clarks Mill near Maheno.
Police, an ambulance and fire appliances from Oamaru and Weston attended the scene after a northbound mid-2000s model Mazda MPV incurred significant damage when it was struck from behind by a heavy truck-and-trailer unit, which was also travelling north.
Senior Constable Ross Lory, of Oamaru, said the Mazda had stopped and was indicating to turn right into Clarks Mill before it was hit by the truck, which had slowed down and swerved in an effort to avoid colliding with the vehicle.
The sole female passenger of the Mazda was assessed by St John staff at the scene but did not require treatment.
The truck suffered minor damage and the driver was not injured, Snr Const Lory said.
The northbound lane of the highway was closed until shortly after 3pm while emergency services cleared debris from the road.
Investigations into the crash are continuing.