Emergency services are at the scene of a serious crash in North Canterbury.

A police spokesman said motorists are asked to avoid State Highway 1 at Spotswood, Hurunui following the crash which happened at 4pm.

State Highway 1/Parnassus Road is closed just south of Macmillan Road, and motorists are asked to take alternate routes.

Three vehicles are involved.

Multiple Fire and Emergency crews along with St John Ambulance crews are at the site.

Chris Lynch Media understands one person has been killed.

Multiple people have been injured, some seriously.

A St John spokesman said they have responded with two helicopters, two ambulances, one First Response Unit and one manager.

The Serious Crash United has been dispatched.