Emergency Services crews were called to the scene of a crash involving a truck between Raurimu Rd and Manson Siding near National Park.
Crews were notified around 9.25am.
A police spokeswoman confirmed the road had become blocked due to the crash.
A St Johns spokeswoman confirmed they sent one ambulance and a rescue helicopter that transported a person to Waikato Hospital in a serious condition.
Emergency crews also received a report around 9.10am of a car colliding with a barrier at the intersection of State Highways 48 and 47 at Tongariro Forest Park.