State Highway 29 Kaimai has now been reduced to a single line of traffic flow for all converging vehicles.
Police confirmed the collision scene is one kilometre up the Kaimai Range from the Matamata end of the hills.
Police said the road was expected to have reduced flow for a period of time to allow heavy transport equipment to remove the goods from the truck, and to remove the trucks from the scene.
Motorists should avoid travelling on the road at this time or seek alternative routes into or out of Tauranga, police have said.
A reporter at the scene said traffic was a nightmare, as there were roadworks happening as well.
"There's roadworks so of the three lanes, only the centre passing lane is open. They're letting through one side of traffic at a time which is causing big delays."
The reporter said traffic on the Matamata side was backed up past the Putaruru turnoff.
Two large trucks have collided on the Kaimai Range, sparking a warning for motorists to take care if travelling on State Highway 29 this afternoon.
The trucks are understood to have been travelling in the same direction on the Matamata side of the range when one appeared to have clipped the other, Northern Fire Communications shift manager Megan Ruru said.
Ms Ruru said no one trapped in the vehicles and it appeared no one was seriously hurt.
Firefighters from Matamata were still responding to the scene, she said.
It is understood the highway is partially blocked and a driver experienced a 'near miss' while travelling.
Motorists are advised to drive with extra care if travelling over the range today.