Though Inspector Jaimie McClelland from Port Stephens LAC admitted that with each passing hour, a happy outcome would be more unlikely.

The 29 year old was last seen snorkelling for lobsters off Birubi Point on Sunday about 6pm. A mate who had been snorkelling with him left and when he returned and failed to find him, quickly alerted Mr McGuire’s father.

“The dad’s been out all night looking for him and then rang us the following morning,” Insp McClelland said.

“We’ve basically been out here since [Monday] morning.

“Given the length of time, if he’s still out there, it’s very unlikely that we will find him alive.”

Police divers were brought up from Sydney and would be searching for at least a couple of days, according to Insp McClelland.

A police helicopter, local command resources and Surf Lifesaving Australia rounded out the operation which was still being classed as a search and rescue mission.

“Until we find something more definite, it’s still a search and rescue operation,” Insp McClelland said.

On Tuesday, police appealed to the public, in particular, any fishermen who were at Birubi Point on Sunday afternoon to come forward and assist with the investigation.

And while it was understood that Mr McGuire left his wallet and other personal items at home, Inps McClelland said there was a slight, but possible chance he had gone to a mate’s house and not notified his family.

Speculation Mr McGuire had been taken by a shark was quashed by police.

“At this stage there’s no indication that a shark was involved at all,” Insp McClelland said.

Mr McGuire is described as being of Caucasian appearance, about 180cm-185cm tall, of a slim build, and with shaved brown hair.

He was last seen wearing red board shorts, black flippers, black goggles with clear snorkel and carrying a small mesh bag.

Anyone with information should contact Crime Stoppers on 1800 333 000 or use the Crime Stoppers online reporting page nsw.crimestoppers.com.au/ Information.