Hunt for teen swept off rocks extends to Christmas Day

An air and sea search will continue on Christmas Day for a teenager feared swept into the ocean from a rock shelf north of Sydney.

Emergency services were called to North Avoca Beach about 3pm on Christmas Eve following reports the 15-year-old boy was missing in the water.

Helicopters circled the area, while police and surf lifesaver crews were on the water.

Volunteers from Marine Rescue at nearby Terrigal were tasked with assisting water police in the search effort.

Marine Rescue NSW Inspector Steve Raymond said a volunteer crew on board Terrigal 30 spent two-and-a-half hours searching waters off North Avoca Beach before being stood down for the day at 7pm.

"Marine Rescue Terrigal volunteers will continue the search at 9am tomorrow morning," he said.

"Terrigal 30 will conduct search patterns in an area to be determined by NSW Police Marine Area Command."

Amid the search on Tuesday, conditions offshore were choppy with a 2.5 to three-metre swell.

Surf Lifesaving NSW chief executive Steve Pearce issued a statement urging people to think twice before taking risks near water, with several major incidents on Tuesday.