UPDATE 3.35PM State Highway 5 is now CLOSED between Oturoa Road and the State Highway 35/5 Roundabout. Please follow the detour route and allow additional time for your journey. Please note the detour route is NOT SUITABLE for heavy vehicles. ^MF https://t.co/83d2UdS2BO
— Waka Kotahi NZTA Waikato/BoP (@WakaKotahiWaiBP) January 16, 2019
In a statement, police said, "a number of people have serious injuries" after the collision.
"There are diversions in place at Dansey Rd and Maraeroa Rd, and motorists are asked to avoid the area if possible."
A St John spokeswoman said there were three ambulances, one Jeep and two helicopters at the scene.
The helicopters had been dispatched from Taupō and Tauranga.
A witness at the scene said she understood the crash happened while the car was attempting to make a u-turn.
The witness said the car was "squished against the side of the truck".
State Highway 5 is closed at the intersection of State Highway 36. Westbound traffic is being diverted north on State Highway 36, left onto Oturoa Rd and right onto State Highway 5.