A police spokeswoman said police were called at 1.40pm following reports of a truck and trailer unit crash with a car.
The road was "completely blocked", diversions were in place and motorists could expect delays, police said.
Diversions were still in place at 3.55pm and a crane had just arrived at the scene to remove the truck.
A police spokeswoman said the crash happened between Ruahihi and Omanawa Rd in Lower Kaimai.
A Fire and Emergency NZ spokesman said one person was trapped after a truck rolled on the Kaimai Ranges.
He said crews got the call out about 1.40pm and three fire appliances were at the scene.
St John's spokeswoman said one person in a serious condition and one in a moderate condition were transported to Tauranga Hospital.
Two ambulances and one rapid response vehicle were sent to the scene following the call at 1.41pm she said.