A budding photographer from the New South Wales mid north coast has captured what she describes as her "Oh-my-God moment", with a shark leaping out of the water during a local surf contest.

Steph Bellamy was at Macauley's Beach on Sunday for the Coffs Harbour Boardriders Club competition and was taking snaps of a group of mothers who had taken to the surf for a special heat.

"I took a shot, but as I stood up there was a splash and I thought, 'what was that?' and hit the button to take another photograph," she said.

"Then I heard the judges say, 'Wow, what was that?' and I expanded the shot out so I could have a look and it was as plain as day there was a major photobomb from a beautiful creature of our planet.

"It was a shark, and quite a large one."

She said the mums and kids were told to get out of the water, but 10 minutes later the competition resumed with the open men's heat.

Ms Bellamy said the swimmers in the water described the shark as "black with a white belly" and "about eight foot long".

"It actually jumped out of the water twice and I somehow, pot luck, caught it with the second shot.

"When everyone saw my photo they said, 'Oh my God, Oh my God, it's not a dolphin, it's not a tuna, it's actually a shark'."

Everyone remained calm, she said, and there were "no meltdowns".

She believed the shark was chasing something when it leapt out of the water.

"He's launched twice at some sort of fish he was after, I think," she said.

"He certainly wasn't after any of the mums, that's for sure, which is a good thing."

The shark species is unconfirmed but Ms Bellamy said some "keen fisherman" in the club believe it may have been a mako, a junior bull shark or a spinner.

Ms Bellamy has been taking photographs as a hobby since age 10 and was surprised this latest effort has attracted such wide interest.

"I had a gentleman from Sky News in the UK just ring me and ask to use the photograph, so it's insane," she said.