The driver had been trapped after the truck crashed into a ditch near Ruahihi Power Station about 12.45pm.
It is understood the driver was now free.
Police requested drivers avoid the area if possible.
EARLIER 1.20pm: The driver of a logging truck that crashed in the Kaimai Ranges is still trapped in the vehicle as emergency services work to clear the highway.
The crash happened about 12.45pm near the Ruahihi Power Station and traffic is now backed up for several kilometres.
Police northern communications Inspector Ian Brooker said the section of State Highway 29 would be closed.
Motorists are advised to use alternative routes until the scene can be cleared.
EARLIER: State Highway 29 has been shut down as emergency services respond to a crash in the Kaimai Ranges.
The crash happened about 12.45pm near Ruahihi Power Station.
Traffic is being diverted to Te Puna.
Police northern communications Inspector Ian Brooker said a logging truck has been involved in a crash. It was unclear at this stage if anyone was hurt.
Emergency services were about to close the road.