UPDATE 4.35PM: State Highway 29 has re-opened in both directions following a serious crash earlier this afternoon.

However, a reporter on the scene has advised that traffic is still extremely heavy in the area and is moving very slowly.

One of the vehicles involved is reported to be a Toyota Land Cruiser with a fully laiden trailer.

Earlier:

Multiple people are reported to have been injured in a car crash on State Highway 29, on the Matamata side of the Kaimai Range.

Western Bay of Plenty road policing manager Ian Campion confirmed to SunLive that there is a crash on the Matamata side of the highway.

He says the crash is believed to be blocking the highway but he is not sure of all the intricacies at this stage.

A SunLive reader has emailed in saying traffic has come to a grinding halt on the Kaimai Range.

The reader says her husband was stuck in traffic for 30 minutes on the Hamilton side before deciding to turn around and head to Rotorua.

She says people are standing beside their cars.

Another reader contacted SunLive via Facebook saying: "Traffic is insanely backed up and at a standstill.

"Had an ambulance and police race past me earlier."

Traffic was at a standstill on SH29 this afternoon.

Keep checking SunLive for more updates.

At the scene? Call: 0800 SUNLIVE or email photos to: [email protected]