"Fortunately, nobody appears to have suffered serious injuries, however the road is completely blocked," it said.
The road is expected to remain closed for some time until logs can be removed.
Motorists should delay their journey or consider using an alternative route, south via SH36 through Rotorua or north via SH2 through Karangahake Gorge.
NZTA said the road was closed between Poripori Rd and State Highway 28.
In a 4.40pm update, it said the highway would be closed for "several more hours"
"Crews are on-site and clean up is underway."
The truck landed in a paddock. Photo / Supplied
The Bay of Plenty Times has heard reports of long queues of cars being turned around on the highway, a major roading link between the western Bay of Plenty and Waikato.
The Powerco website says there are 106 properties in Lower Kaimai, near Soldiers Rd, currently without power due to a vehicle striking a pole.
The estimated time for power to be restored was 8pm.