Resident of Lake Cathie for 28 years Brett Dolsen managed to capture a photo of the shark near the bridge.

"It was difficult to get good photos in the shade but when I first saw it I knew this was something unexpected and turtle came to mind," Mr Dolsen said.

"As it came closer the distinct swaying swimming pattern said shark, but the size of the rear fin confused me and made me think it was two. I did think dolphins at one stage but no it was definitely one shark making it's way back to the little bridge.

"I lost sight when I thought it was going under the bridge."

Mr Dolsen said it is the first time he has seen a shark in the waterway but according to long-time lake residents, it is not uncommon when the waterway is open to the ocean.

"I think people should just be cautious at the moment and treat our visitor with respect," he said.

A Port Macquarie-Hastings Council spokesperson said while council does not keep records on shark sightings, bull sharks known to access local waterways on occasions. While the species of this shark is not yet known, from a safety perspective, people are encouraged to exercise caution and make sound decisions before entering any waterway.

There has been an increase in shark activity off the Port Macquarie coast with schools of bait fish and migrating whales attracting more shark numbers.

A 35-year-old woman, Chantelle Doyle, was attacked by a juvenile great white off Shelly Beach on August 15. She was pulled to the shore by her husband with severe leg lacerations and has undergone surgery at John Hunter Hospital.

She is in a stable condition and recovering.

While you're with us, you can now receive updates straight to your inbox from the Port Macquarie News. To make sure you're up to date with all the news, sign up here. If you would like to support our journalists you can subscribe here.