Grave fears are being held for a 28-year-old rock fisherman from Winston Hills in Sydney who was swept into the ocean at Mermaids Inlet, near Jervis Bay, early Monday morning.
The man was fishing with three friends when he went to collect a container near the water about 1am and lost his footing.
One of the man's friends threw a life ring into the ocean. However, Marine Rescue personnel recovered the device later.
Police have been told the man could not swim and was not wearing a lifejacket.
A full-scale sea and air search was launched about 2.20am, involving the NSW Ambulance helicopter, PolAir, the Surf Life Saving NSW helicopter and multiple Marine Rescue NSW vessels.
But it was scaled back by mid-morning.
Rough seas hampered the search, and by 1pm only local police were left to continue foot patrols. Divers were expected to enter the water once conditions became calmer.
Marine Rescue Illawarra regional controller Bruce Mitchell said crews were not giving up.
And if conditions improved, crews would re-enter the water.
"It's not a real good place to be in that location," Mr Mitchell said.
"You get the backwash off the cliffs and it makes it very uncomfortable in a boat out there.
"There's about a 1-metre swell, but as it rolls in it hits the cliff and creates turbulence. The swells are pretty solid as they're hitting the cliff - there's a lot of force in them."
During the operation, Marine Rescue vessels conducted a grid search out to one nautical mile off shore.
The man's disappearance has prompted police to issue a fresh warning about the dangers of rock fishing.
Police superintendent Mark Hutchings said rock fishing could be a high-risk activity even in calm conditions, and it could lead to disaster in rough conditions.
"Before you head out, check the tides, swell and weather forecasts for the time you intend to be out," Supt Hutchings said.
"If you decide it is safe to head out, have a careful look at conditions before venturing onto a rock platform. Most importantly, always wear a lifejacket and proper shoes.
"Even the most experienced rock fishermen can be swept into the water and a lifejacket can be the difference between a frightening experience and disaster."
The body of a man who went missing after swimming in the Murray River at the weekend has been found. The man, 44, from Mount Pritchard, was camping with his family when he went for a swim alone in the river near Bruce's Bend at Yarrawonga, on the NSW-Victoria border, about 5.30pm on Saturday.
Emergency authorities searched the area over the weekend and resumed the search yesterday morning.
Police said an SES volunteer found the man's body about 9am, a short distance from Bruce's Beach.
There aren't believed to be any suspicious circumstances.