A St John spokeswoman said earlier that one patient in a moderate condition was transported to Waikato Hospital by road while another was transported by road in a serious condition.
The Westpac Rescue Helicopter was also called to the scene.
The crash happened within minutes of a truck rolling further south on State Highway 1 towards Kinleith, the police said.
That driver was not injured but firefighters were cleaning up a huge diesel spill.
Motorists have been asked to avoid the area. A detour around the roadblock was in place via State Highway 32, Whakamaru Rd and State Highway 30, Ongaroto Rd.
SH1 TOKOROA - ROAD CLOSED - FINAL UPDATE 6.20AM
State Highway 1 between Galaxy Rd and Campbell Rd, south of Tokoro...