State Highway 29 is closed following a serious crash.

A police spokesperson says there is a serious crash on the Matamata side of the Kaimai Range.

"The crash reportedly involves two vehicles and the serious crash unit has been notified.

Police say the road is closed and diversions are in place.

"Motorists should expect delays.

"Due to a serious crash, SH29/Kaimai Range is closed in both directions between Cambridge Road and Rapurapu Road," says a roading alert from NZTA.

"Delay your journey or allow extra time for a detour."

Alternative route: divert down SH28, SH5 and SH36.