State Highway 1 has been reopened after three vehicles, including a petrol tanker, crashed at Ohakuri this morning.
The petrol tanker driver is in a serious condition and was flown to Waikato Hospital.
St John confirmed it sent two ambulances to the crash following the emergency call at 7.40am.
Just before 9am, Fire and Emergency New Zealand northern shift manager Paul Radden said the driver of the tanker was trapped but crews had "extricated him".