A helicopter is responding to a serious two vehicle crash on State Highway 1 at Hundalee.

A police spokesperson said police were notified of the crash at the intersection of Hundalee Road and Claverley Road at 3.15pm on Tuesday.

The road has been reduced to one lane.

Police had no confirmed information about injuries but said Fire and Emergency New Zealand had advised nobody was trapped.

A St John spokesman said an ambulance was sent to the scene and a helicopter was on its way.

NZ Transport Agency said stop go traffic management and a temporary speed restriction were in place near the Claverley Road intersection.

Motorists were advised to drive carefully and expect delays.