Rescue crews are continuing to comb waters off the NSW mid-north coast for an experienced sailor feared drowned after being swept from a yacht in a "perfect storm".
Mal Lennon, 62, was at the helm of the 36ft yacht Amante when he was struck by a huge wave that knocked him into the water off Broughton Island about 11.30am on Wednesday.
Conditions have eased but crews searching for Mr Lennon believe there is little chance he could have survived the night in brutal seas without a life jacket.
"Sea conditions were up to six to eight metres with sometimes up to 50-knot gales," Superintendent Mark Hutching told reporters on Thursday.
"Due to the sea conditions we do believe that this will be a recovery mission."
Supt Hutching said the search has been difficult because of the "perfect storm" conditions.
Mr Lennon was returning to Sydney after competing in the Pittwater to Coffs yacht race over the new year break.
Mr Lennon, who has an adult daughter with his former wife, is a civil engineer by trade but has been a property manager with Cadence Australia for a decade.
His boss Todd Murphy, whose father has known Mr Lennon for more than 40 years, told AAP the news had come as a shock to staff who were numb and in distress.
"Mal was a one off. He was an incredibly smart person. It's of no surprise he was on a boat doing what he loved," Mr Murphy said.
The Lane Cove 12ft Sailing Skiff Club paid tribute to Mr Lennon on social media.
"As a long standing club member our thoughts are with Mal's daughter and his family. Vale Mal Lennon," the club posted on Facebook.
The recovery mission will be suspended at nightfall on Thursday, with crews set to make a decision on resuming the search first thing on Friday morning.
In southern NSW, a rescue helicopter has dropped off food and supplies to 41 campers stranded since Sunday in the Deua National Park west of Moruya.
The SES is planning to evacuate the isolated group when floodwaters enveloping them subside on Saturday.
As conditions ease across NSW, emergency crews are hoping residents forced to flee the town of Raymond Terrace near Newcastle will be able to return home by Thursday night.
Meanwhile, crews in the hardest hit areas in the Hunter region spent the day delivering assistance to those stranded by weather or surveying storm damage.
The town of Wallalong, near Port Stephens, remains isolated but most minor flooding is expected to recede by midnight.