A New Zealander has been picked up from his life raft in three metre seas and 30 knot winds after his yacht sunk off the coast of Norfolk Island.

A Defence Force Hercules aircraft and a commercial fishing boat were called into help search for the man after he activated a distress beacon at 6:15am, 166 kilometres east of Norfolk Island.

Photo: Supplied to RNZ

The C-130 Hercules spotted the man, who was being buffeted by strong winds and 3m swells, just before midday.

A commercial fishing vessel MV Norfolk Guardian was en route to pick him up but was not due to reach him until 3pm.

Search and Rescue Mission Coordinator Dave Wilson said the man got into trouble about 4am when his mast broke and went through the hull.

"His yacht sank but he was able to get into his life raft and set off his emergency locator beacon, which is an essential piece of emergency equipment that we recommend everyone have."

Mr Wilson said the rescue was hard due to the rough conditions.

"It was very challenging, the ship crew did a great job considering the three metre seas and 30 knot winds - they launched the ship's rescue boat because it was so choppy, it took a bit of time to get him on board but they were able to get it done."

He said although life rafts were made to last a long time, the man would have been very uncomfortable considering the conditions he was facing.

"The ship is going to its intended destination of Norfolk Island and they should land just before midnight.

"The Norfolk Island Police and the Ministry of Foreign Affairs and TRade and working to make sure the man has all the help he needs," Mr Wilson said.

The man was sailing single-handed from Vanuatu to Marsden Point in a 10 metre sloop called the Waimanu.

-RNZ