A reporter at the scene said the army truck was down a ditch, and had crashed into a fence, with the car in front of it. The car's driver side was extensively damaged.
Military police are on site as is a police photographer, the Serious Crash Unit and an ambulance.
Another army truck is also on site.
Diversions were in place and motorists were advised to avoid the area.
MidCentral District Health Board communications advisor Dennis Geddis said the woman was in a stable condition and was being assessed in the hospital's Emergency Department.