St John crews assessed and treated two patients in critical condition who were airlifted to Waikato Hospital.
Another patient is in a serious condition and was airlifted to Rotorua Hospital.
Three other patients were in a moderate condition and were transported to Taupō Hospital.
The final patient was in a minor condition and was treated at the scene, St John said.
Motorists are asked to avoid the area and to take alternative routes where possible, as the road is likely to be blocked for some time, a police spokesperson said.
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