Dozens of humpbacks churn up the water in a feeding frenzy on the NSW Far South Coast

"It was absolutely insane. It was like sensory overload because you could actually hear and smell them," photographer David Rogers said.

While their annual migration attracts visitors all along the NSW Far South Coast, this activity in water near Haycock Point in Ben Boyd National Park was unprecedented, Mr Rogers said.

Merimbula Marina owner Jessica Miller watched the weekend's feeding event, and said a whale-watcher had tolder her it was the biggest number of whales he'd seen working together in his 24 years of whale-spotting.

"It was an amazing natural wonder. It was amazing to see that number of whales feeding," she said. "Once you have an encounter you realise they are amazing animals.

"People have a real connection with them."

Photos and video shared to Merimbula Marina's Facebook page has been seen and shared by hundreds.

"Feeding events like this do not happen often and when they do they often leave us speechless!" the company posted.

"The raw energy was palpable and it was hard to know where to look. We are feeling very blessed to have been able to witness such an incredible natural wonder.

"Who knows how long they will stay on the Sapphire Coast but it is a timely reminder of how important it is to look after our oceans. They are home to so many wonderful and majestic animals. It was definitely another afternoon to remember!"