One person is critical and two others are injured after a crash on SH47 near Tongariro Forest Park.
Shortly after 1.30pm police and ambulance crews and Taupo's Greenlea rescue helicopter were called to the north side of Mt Ruapehu.
A northern communications ambulance spokeswoman said the critical patient is being transported to Rotorua Hospital by helicopter while two other people are being taken by ambulance to Taupo Hospital.
A fourth person was treated at the scene of the two-car crash for minor injuries.
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