The search for a missing fisherman on the New South Wales south coast has been called off, after the discovery of an empty boat more than 100km offshore.

The search was launched on Saturday evening after the fisherman failed to return from a fishing trip about 8pm.

The 56-year-old man was last seen when he set off from the Batemans Bay Marina at about 6am that day.

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He was manning an 8m Arvor cruiser and had last been spoken to about 10am, police said.

The search area was expanded to as far as Port Stephens in the north and south to the Victorian border.

About 1.20pm on Tuesday, an Australian Maritime Safety Authority Challenger aircraft located an empty boat about 80 nautical miles — or 148km — east of Narooma.

Fisherman on board a nearby commercial fishing vessel assisted police to stop the vessel in challenging conditions before it could be towed to shore.

Police said patrols by Marine Area Command will continue in the coming days, however, the main search had been suspended.