"The vehicle was flat as a pancake. We're lucky we're not looking at a fatality."
The female was taken to Dunedin Hospital by ambulance with minor to moderate injuries, although she is understood to have deteriorated after leaving the scene, and the male was taken by Otago Rescue Helicopter with moderate to serious injuries.
The pair were yesterday both in stable conditions, the woman in the high dependency unit, and the man in the coronary care unit, a hospital spokesman said.
Mr Lloyd said the accident was witnessed by a cyclist who notified emergency services after cycling to the top of a hill to get mobile phone reception.
It was fortunate someone saw the accident, he said.
"They may have been there for some time if the cyclist hadn't seen them. They were difficult to see from the road," he said.
"We may only have started looking for them when a family member rang to say they were missing."
Mr Lloyd said police were still investigating the cause of the accident, and asked the cyclist who witnessed the accident to get in touch to assist with the investigation.