Two men have been rescued from stormy seas off Niue after their yacht capsized yesterday.

The American skipper of Anna, a 17m catamaran, and his New Zealand crewman were about 233 kilometres west of Niue when they set off their emergency locator beacon about 4pm.

An Air Force P3 Orion located the men, one still on board Anna, and one in an inflatable dinghy, about 11pm and watched over them until cargo ship Forum Pacific picked them up at 6am.

Rescue Coordination Centre New Zealand (RCCNZ) spokesman Mike Roberts said the fact the beacon was GPS-enabled had greatly assisted the men's rescue.

"We were able to accurately pinpoint the location of the vessel and send the Orion directly to the scene. Given the stormy conditions, the speed that we were able to reach the men made a huge difference to their safety," he said

"Furthermore, the fact the beacon was registered meant we were able to contact the skipper's wife and obtain information as to who was on board and what kind of equipment they had with them."

The men were now safely on board Forum Pacific en route to Niue.

A navigation warning had been broadcast to other vessels advising of the location of the capsized catamaran, Mr Roberts said.