Witnesses to the crash said a van and truck had crashed and the van had spun around on the road.
Motorist Jeremy Parslow was about four cars behind the crash when it happened.
"[It appears] the van was coming up the Kaimais and it had a head on with a truck and it's spun around. The front of it's completely crushed."
The van appeared to be heading up the hill towards Matamata when the crash happened near the summit, he said.
Mr Parslow said fire fighters were cutting the driver from the van.
Three fire trucks, an ambulance and four police cars were at the scene, he said.
3.08pm: Emergency services are on their way to a serious crash on SH29 near the top of the Kaimai Range.
Police said the road was blocked so motorists should expect delays if travelling that way.
It is not yet known how many people were involved or their injuries.
