Christchurch’s Southern Motorway has reopened following a crash involving a car and truck which left one person seriously injured.

A police spokesperson told chrislynchmedia.com the crash happened about 3pm today.

A St John spokesman said an ambulance and rapid response vehicle were sent to the scene.

Two patients were assessed, with one taken by ambulance to Christchurch Hospital in a serious condition.

The second patient did not require transport to hospital.