Two men have drowned and one is missing in big surf off the New South Wales mid-north coast.

The group of six people got into trouble at Moonee Beach, north of Coffs Harbour, just after 6pm on Monday, police said.

Two men, aged 35 and 45, were pulled from the water but did not survive.

Emergency services called off their search for a 28-year-old man after sunset amid deteriorating conditions but were due to resume on Tuesday morning.

Two teenage girls and a teenage boy were also pulled from the water and taken to Coffs Harbour hospital for observation.

Police were working to establish if the group, from western Sydney, was a family on holiday – it is believed they all knew each other.

Surf Life Saving NSW north coast duty officer Les Pepper said the search had now moved to the back beach of the unpatrolled Moonee beach.

“It is a treacherous stretch of beach, not safe at all,” he told ABC News on Tuesday. “Some of the beaches are really nice, they look really nice, but are a bit treacherous.

“At Moonee, it is a river mouth, the creek comes out from there and the rip forms from there and takes you straight out, and people just don’t understand what rips are.”

He urged people to only swim at patrolled beaches, with many now patrolled seven days a week over the Christmas period.