Emergency services are currently working at the scene of a serious crash at the intersection of Orari-Rangitata Highway and Rangitata Island Road.
Police were called to the scene about 4.30pm.
Police say early indications are one person is critically injured, and two others are seriously injured.
The road is closed between Orari-Rangitata Bridge Highway and Ealing Road.
Diversions are in place through Arundel.
Motorists are asked to avoid the area.