PHOTO: ODT FILES
Emergency services were alerted to the incident in the small settlement of Waipapakauri at about 4.40pm on Thursday.
Police, as well as two helicopters, two ambulances, two St John rapid response units and an operations manager responded.
"At this stage three people are in a serious condition and four people are in a moderate condition.
"Some of those injured will be airlifted to hospital."
State Highway 1 has now reopened after earlier being closed in both directions.
