Earlier, two people were injured in another serious crash on State Highway One in Pukerua Bay, Wellington.
Two motor vehicles collided head on at 5.54pm, resulting in the road being blocked.
Two people were taken to hospital in ambulances.
Police have been able to open one lane and are directing traffic alternating between south and north bound vehicles.
"Motorists are asked to be patient, expect delays in their travel and abide by the directions of staff that are assisting to move traffic through the area," police said in a statement.
One lane is expected to be closed for some time, and motorists are asked to consider delaying their travel for an hour or so in the meantime.
All three emergency services, being fire, ambulance and police, attended to both accidents.