A woman who lay trapped and injured in her car for 17 hours after it careened down an embankment into a creek on the NSW South Coast is "very fortunate" to be alive, authorities say.
The woman, aged in her late 60s, was knocked unconscious after her car left the road and ended up in Kianga Creek between Moruya and Wallaga Lake about 11pm on Wednesday.
She eventually woke up and called her daughter-in-law in a "distressed state" after 4pm on Thursday but wasn't able to give her exact location, NSW Police Chief Inspector Peter Volf said on Friday.
The crash site could not be seen from the road and mobile phone towers are sparsely scattered across the region.
But police, ambulance, firefighters and State Emergency Services managed to find the car within 20 minutes of being alerted by using the driver's mobile phone location.
The vehicle ended up on its wheels, Chief Insp Volf said, but may have rolled after it left the road.
The woman was relieved and in good spirits when rescuers finally found her.
"She's a very, very fortunate lady to be in the position she's in today," the chief inspector told reporters in Bega on Friday.
"There have been some other accidents north of that location."
The woman was airlifted to Canberra Hospital in a stable condition to be treated for suspected broken ribs and exposure.
The overnight temperature in the region is believed to have dropped to between 2C and 3C.
"Sitting in a car, next to a creek, it would have been freezing," Chief Insp Volf said.
Police are investigating the circumstances of the crash.
