He said one woman had serious injuries, although both women were conscious when fire crews arrived.
The white hatchback in which the pair were travelling had come to rest on the roadside and one fire appliance, two ambulances and multiple police officers had attended the scene.
The Lifeflight Trust Westpac Rescue Helicopter was called and landed at the nearby Opaki Racecourse, ready to transport one of the women to Wellington Hospital.
The other woman was taken to Wairarapa Hospital by ambulance but the nature of her injuries was not known.
Hospital spokeswoman Jill Stringer said the woman was in "satisfactory and stable" condition, although it was not clear whether she would stay overnight in hospital.
Police were unavailable for comment at the time of going to press.
