An investigation is underway into a pile-up between a truck and three cars in Hunterville overnight.
The collision on State Highway 1 left six in hospital.
St John confirmed five ambulances and a helicopter were sent to the wreckage.
Two patients went to Palmerston North hospital, one airlifted, and the rest went to Whanganui Hospital.
The road has now reopened.
Hunterville is east of Whanganui.
