State Highway three is closed and several people have been taken to Te Kuiti Hospital following a crash about 3km north of Te Kuiti in atrocious weather this afternoon.
Senior Sergeant Robert Van Kalken of Te Kuiti Police said emergency services were called to the intersection of SH3 and Oparure Rd about 2pm.
"It appears a northbound 1999 Mazda saloon has had a minor collision with a truck and trailer unit turning right on to Oparure Rd in atrocious weather conditions.
"The Mazda has then slid out of control over the centreline into the southbound lane colliding head-on with a 2006 Honda Civic," said Mr Van Kalken.
An elderly Taumarunui couple travelling in the Civic with their grandchildren suffered minor to moderate injuries in the crash while the children in the backseat were shaken but unhurt.
The male driver of the Mazda was seriously injured in the crash while a woman travelling as a front seat passenger suffered what is described as critical injuries.
Conditions at the time of the crash were described by Police as atrocious with heavy rain, slippery road conditions and poor visibility.
Mr Van Kalken recommended those travelling in the area to drive with their headlights on and to match the speed of their vehicles to the road and weather conditions.
"It would be better to arrive at your destination a few minutes later than not at all," he said.
All of the injured were taken by ambulance to Te Kuiti Hospital, at this time the inclement weather has prevented the seriously injured patients being evacuated to Waikato Hospital by air.
Members of the Waikato Serious Crash Unit are investigating the crash.