The multi-vehicle crash in Porirua that occured at approximately 12.30pm involved 1 car and 4 motorcycles.
As a result of the crash, 5 people have been taken to hospital.
One of the motorcyclists was critically injured and was flown to Wellington Hospital by a rescue helicopter.
The remainder of the patients were sent to Wellington and Hutt hospitals by ambulance.
The State Highway North of Tawa has been closed to northbound traffic to allow the patients to be safely treated, and to allow the rescue helicopter to land on the road. The road remains closed while the Police Serious crash team conduct a scene investigation.
The cause of the crash is not yet known.