"The injured parties were occupants of both the cars while no-one travelling on the bus was injured."
Traffic on the SH1 was delayed for about an hour while diversions were put in place prior to the highway being partially re-opened.
"On first inspection, it appears the steel wire median barrier functioned correctly and helped prevent a potentially fatal head-on crash."
Mr van de Wetering said an investigation is now underway and to assist investigators police would like to anyone who saw the accident to contact the Huntly police station on 07 8287560.
Police are also investigating the cause of a single vehicle crash near Te Kuiti about the same time.
The driver of a car lost control and crashed into a gully off Ahoroa Rd, about 1km from the meat works plant outside Te Kuiti, and was taken to Waikato Hospital by ambulance with serious injuries.