Port Stephens' blue water wonderland isn't just popular with the tens of thousands of tourists who visit each summer. New research shows the estuary is inhabited with far more great white sharks than previously thought.

And many of them swim less than 100 metres away from oblivious holiday makers at places like Fly Point.

"This project has changed our whole view of how sharks behave in Port Stephens," marine scientist and lead researcher David Harasti said.

"We thought they stayed off Hawks Nest, but now we know they come right inside the estuary, right up to places like the Anchorage."