The serious crash which forced police to close down State Highway 29 on Tuesday, remains under investigation.

One person was flown to Tauranga Hospital in a serious condition following a crash between a ute and truck just before 1.30pm.

A police spokesperson says the crash happened on the Matamata side of the Kaimai Range, near the summit.

The road was closed in both directions for several hours, while the serious crash unit examined the scene.

The highway was re-opened just after 6pm.

Anyone with information about the crash can contact the police 105 non-emergency line.

Alternatively, information can also be left anonymously via the Crimestoppers 0800 555 111 line.