A car rolled and crashed into a median barrier after narrowly missing a parked vehicle on Christchurch’s Southern Motorway.

Emergency services were called to State Highway 76 in Halswell shortly after 11am.

Motorist Letitia Andrews said she saw the car come close to hitting a vehicle parked on the side of the motorway before it swerved, lost control and rolled into the barrier.

A police spokesperson said officers were notified of a single vehicle crash which blocked the right eastbound lane.

A St John spokesperson said an ambulance responded, and one patient was assessed and treated in a minor condition at the scene.

The motorway was clear by about 1pm.