A truck has broken down and is blocking the eastbound passing lane of the Kaimai Range.
A police spokeswoman said the breakdown on State Highway 29 happened at 8am today.
She said it was 1km from the bottom of the hill on the Matamata side, but could not confirm whether it was causing traffic build-up.
She said a tow was being arranged.
The New Zealand Transport Agency advised in a tweet that motorists should take extra care when passing the scene.