But as she clocked up the kilometres and the heavy fog receded to reveal Pokolbin's vineyards, the 38-year-old mother of four from Caves Beach kept running.

She started to believe she could win.

And win she did, reining in Sydney runner Anna Heath in the final 15km of the 42km event.

The victory was Parry-Williams's first marathon win in her five-race career, but her time of three hours and 16.37 minutes was her slowest.

"I've been injured for a year and I wasn't even planning to race, I just started and ran the first 10km with a friend for a training run really," Parry-Williams said.

"It just happened by chance that I started feeling good and I left my friend behind and gradually caught the other girls."

Parry-Williams said she could have caught Heath before the halfway mark but decided to hang back and bide her time.

"Before halfway I got pretty confident I would [win] because I could see at the turnaround that the other girls were working quite hard to keep the pace they were at and I felt very comfortable," she said.

It was the Caves Beach surf lifesaver's first marathon since suffering a stress fracture in her foot 12 months ago. She sustained the injury when a minor ailment she carried into the Gold Coast Marathon flared up after the race.

Although Parry-Williams finished seventh in her best time of two hours and 53 minutes, it proved a major setback.

The benefit of restricting her running training has been an increased focus on swimming and cycling and a growing passion for ironwoman events.

"As a get older I find I that with the injuries I've had it [swimming and cycling], it suits me better because I vary my training," she said. "I couldn't run every day, my body isn't coping with that."

The next event on Parry-Williams's calendar is the 100km Oxfam Trail Walk teams event from the Hawkesbury River to Sydney Harbour on August 27.

Sydney runner Darren Moyle won the men's winery marathon for the second straight year in a time of two hours and 49.52 minutes, while East Maitland's Tony Anderson was the Hunter's best, finishing fourth in 3:01.21.

Former Knights fullback Robbie O'Davis came 13th in 3:21.00.