This story was updated because it originally referred to the crash area being in the Tasman district.
A truck has blocked part of State Highway 1 on the east coast of the South Island near Hundalee in the Hurunui district this afternoon.
A truck's trailer unit rolled over between Birches and Hundalee roads, blocking the road.
There are no reports of injuries.
Emergency services were notified about 2.50pm.
Diversions are being put in place, however, police are warning motorists to expect delays.