Surfers have been warned to steer clear of a large southern right whale at Freshwater beach after they were seen within metres of the animal.
The whale was first spotted around 9am on Sunday morning just beyond the break at the beach, heading towards North Curl Curl.
Freshwater resident Ian Hansen says he spotted it because it was ringed by surfers.
"To be honest they were harassing it a bit. They were so close and it had no room to move," said Mr Hansen, estimating they were as close as two metres. "If I was the fish I'd be harassed too. It'd move a bit and they'd back off."
Swimmers are required to stay 30 metres from whales. Surfers and boats need to stay at least 100 metres away.
"I was pretty worried to see one guy out there with a kid on his board. It's a big animal, one tail flick and we could have a death on our hands," Mr Hansen said.
Locals called the Department of Fisheries and the Department of Environment and Heritage.
The surfers were told to back off via the Freshwater Surf Life Saving Club loudspeaker.
Club executive officer Wayne Freakly said he was concerned because southern right whales are known to be a bit flighty. They can weigh more than 70 tonnes. A surfer was taken to hospital last year after a run-in with the same breed at Bondi.
"The whale was within the confines of our beach, just having a sticky beak and some riders went out to have a look," Mr Freakly said. "We reminded them to move back and stick to the protocol."
Department of Environment and Heritage spokesman Lawrence Orel told Fairfax Media it was probably either a near-term pregnant female looking for a safe calm area to calve or a young male exploring.
"It's probably not sick or hurt. It's called a southern right whale because if you were going to hunt whales, this is the right one, as they move slowly near the surface and are easy to get."
According to the department, the whale is likely to be the same whale that was spotted off Coledale Beach on Saturday.
A spokesman for the NSW Marine Police told Fairfax Media they dispatched a vessel to patrol the area to ensure neither the spectators or whale are injured.