Yanko said the accident happened on a road near Normanby, south Taranaki this afternoon.
The injured were flown by Taranaki Rescue Helicopter to Taranaki Base Hospital.
A person who was performing CPR on one of the injured riders was also taken to hospital after suffering a heart attack. He was believed to have been one of the occupants in the van.
State Highway 3 has been reopened and the Serious Crash Unit are still investigating.
At 12.35pm this afternoon seven people were taken to hospital in a critical condition following a two-car crash on State Highway 1 at Te Hana in Rodney.
A male driver was cut from the wreckage and airlifted to Auckland Hospital. The others in the cars, who were of varying ages, were transported to hospital in critical condition.
This morning a 21-year-old farmer was killed in a head-on crash after his motorcycle and a car collided on State Highway 2 near Opotiki at 5am.
The motorcyclist, who lived and worked in the area, died at the scene. Police said the two occupants of the car were not injured in the crash.