A man and woman have expressed gratitude for being back on dry land after they were rescued from a stricken yacht on the New South Wales South Coast on Tuesday. 

Brett, 60, and Lisa, 48, were found "safe and sound" about 170 nautical miles east of Nowra at around 7:30am.

"I am so pleased to say that this rescue operation has been a resounding success," NSW Marine Area Command Acting Superintendent Siobhan Munro said.

The rescue mission was launched off the South Coast after a distress beacon was activated about 1pm on Monday.

At the time, the yacht was 85 nautical miles from Sydney, and had drifted 160 nautical miles offshore by the time emergency services reached Brett and Lisa.

"That's how strong the winds were and how fast it was, pushing the vessel away," NSW Marine Area Command Sergeant Ryan Spong said of the conditions.

The 19-metre vessel, Spirit of Mateship, had experienced mechanical failure and was taking on water, Ben Flight from the Australian Maritime Safety Authority said on Tuesday morning.

It's believed Brett and Lisa left Jervis Bay on Sunday or Monday for Sydney, NSW Marine Area Command Chief Inspector Anthony Brazzill said.

On Tuesday, a multi-agency operation retrieved the pair "in some quite horrendous conditions", Sergeant Spong added.

The pair were taken on board NSW Water Police vessel Nemesis, and thanked everyone involved in their return to Sydney.

Lisa said she was feeling "safe and secure and happy" despite not getting much sleep last night.

Brett said the waiting was "alright" and that the boat was "safe" and "more than seaworthy".

"It was more we were tired, seasick, we couldn't continue any further," he said.

"That was a decision we made to call ... it could have got worse ... I think we made the right decision."

The Nemesis passed through Sydney Heads just before 6pm, before the pair were met by family in Balmain half an hour later.

Spirit of Mateship, which has raced in several Sydney to Hobart yacht races, was abandoned at sea.