"It came to rest about 100m down the bank and trapped the woman. She was able to use her cellphone to raise the alarm. I understand that she got in touch with her husband but she wasn't sure where she was and that could be the result of the head injury," Ms Kennett said.
Her husband contacted emergency services, with fire communications then working with the woman to pinpoint her location, she said.
Emergency services were originally sent to State Highway 10 near Puketona and Bulls Gorge, about 25km north of the crash. They scoured roads in the area with the woman asked to listen out for sirens. Police managed to track her location by using the signal of her cellphone.
"When the police and fire eventually found her, they had to secure the car to get her out," Ms Kennett said.
She was found about 50 minutes after the crash.
Police were still investigating why the car left the road, Ms Kennett said.
It was believed the woman was travelling from Waipapa to Paihia but had taken a different route to the one she usually drove.
Kerikeri Volunteer Fire Brigade chief fire officer Les Wasson said she was in a "pretty good" state when emergency services arrived.
She was unable to get out of the car because of the "extensive" damage, but the firefighters managed to pry a door open, Mr Wasson said.
At least six firefighters carried the woman in a stokes basket - a stretcher used for difficult rescues - up the muddy, steep bank.
They used three or four ropes attached to a St John vehicle to stabilise themselves.
A St John spokesman said the woman was taken to Bay of Islands Hospital in Kawakawa with a moderate head injury.
She was "very lucky" considering the distance she dropped, the spokesman said.
A hospital spokeswoman said the woman was in a stable condition late yesterday.
