A rescue helicopter is currently on the scene of a serious single-car crash near Huntly where one person with critical injuries is being treated.
A spokeswoman for St John said they responded to the incident on Rotowaro Rd, west of Huntly after a car crashed into a ditch.
Meanwhile, two other people have been transported by ambulance to Waikato Hospital, one with serious injuries and the other with minor injuries.
Emergency services were called around 3.15pm. As of 5pm, the St John spokeswoman said the patient with critical injuries had not been transported away from the scene.
Police advise the road is currently closed and motorists are asked to avoid the area.