State Highway 29, the Waikato end of the Kaimai Range, is closed as Police respond to a serious crash.

"The two-vehicle crash occurred at around 3.15pm, just east of the intersection with Rapurapu Road," says a police spokesperson.

"Initial reports are that there are serious injuries.

"The Serious Crash Unit has been notified.

"People are advised to avoid the area and delay travel."