A six-year-old boy walked nearly 2km early this morning to get help for his mother, after their vehicle crashed into a river on the West Coast.
Police said the boy tried to get his 41-year-old mother out of the car when it crashed into the Arahura River, but she was swept away.
He then walked about 2km to State Highway 6 where he was found just before 2am by a member of the public.
Sergeant Mark Kirkwood said a full scale search and rescue operation was launched involving volunteers, Fire and Emergency, Surf Life Saving, the Coastguard and jet boaters.
Sergeant Kirkwood said her son did extremely well.
"Extremely tired, he was cold, wet, he was covered in mud. I thought he was very resilient of the conditions he was put through and he come through the other side."
Sergeant Kirkwood said a local found his mother several hours later at about 730am, on a beach north of the rivermouth.
"A resident who resides about 7km away from where the crash happened noticed a lady coming out of the water, from the ocean, and rendered her assistance and we found out that was the mother of the six-year-old."
She was being treated for hypothermia in Greymouth Hospital, police said.
The boy was unharmed and being cared for by relatives, they said.