Two drivers were seriously injured after a head-on collision on State Highway 1 near Tirau tonight.
Emergency services were alerted to the incident at Piarere, near Lake Karapiro, about 9.15pm.
One driver was airlifted to Waikato Hospital in a critical condition by the Westpac Rescue Helicopter.
Three others were taken by road - one in a serious condition and two with moderate injuries.
The northbound lane of SH1 is closed with a diversion in place. The police serious crash unit is investigating.