He quickly discovered the woman in the driver's seat and a poodle on the passenger's side and the car was full of smoke.
Mr Gyton, who has been a volunteer firefighter for 12 years, said his firefighting training for emergency situations kicked in.
"I looked at the boats to see what way they were facing. The tide was coming in pretty fast," Mr Gyton said.
"The scariest part was it was full with smoke with all the wires fusing. I was concerned about it catching on fire.
"I made the decision to pull her out and get her away from that car."
But first he got the dog ashore safely and then returned to carry the woman to nearby rocks. The water was up to the top of his thighs as high tide at 11am approached. By then about six people had stopped to help.
"A midwife was there and she did some first aid to a cut on the lady's head. Everyone was working together and it was absolutely fantastic."
Mr Gyton's wife rang for the fire service and crews from Whangarei and Onerahi arrived.
The woman was put on a stretcher and carried to a flat grassy area where she was put in an ambulance and taken to Whangarei Hospital. The woman was in a stable condition late yesterday and was kept in over night.
It's believed she had head, chest and leg injuries.
The road was closed while a crane was used to haul the car from the water onto the back of a tow truck.
The corner has been the scene of a number of crashes.
Whangarei District Council spokeswoman Ann Midson said the corner at Fishermans Point had undergone an accident black spot review and as a result there had been significant safety work done.
More than $125,000 had been spent which included 300 metres of guard rails, additional signs, edge marker posts, rumble strips and widening the road with concrete "aprons" which stopped gravel washing onto the road surface.
Ms Midson said engineers would visit the site following yesterday's crash to see if there was anything more that could be done to make the corner safer.
