NZ Defence Force finds father and son missing on fishing trip near Tonga since Saturday

A father and son were spotted by rescuers waving their T-shirts from Hunga Tonga island. Photo/Supplied

A man and his son have been rescued after they went missing at sea off the coast of Tonga three days ago.

The duo, from Tonga, failed to return from a day-long fishing trip off Eua Island on Saturday, but NZ Defence Force (NZDF) searchers spotted them today waving their T-shirts from Hunga Tonga island, about 58 kilometres northwest of the Tongan capital of Nuku'alofa.

The NZDF had been called in to help because the local search was unsuccessful and the force's P-3K2 Orion had better search capabilities.

Air Commodore Darryn Webb, the Air Component Commander, said the Orion from the Royal New Zealand Air Force's 5 Squadron spotted the two about an hour into the search.

Crew from the Orion reported the survivors appeared to be well and their blue wooden boat intact.

The pair's boat appeared in tact when the air crew spotted it. Photo/supplied

Webb said the aircrew dropped the survivors emergency supplies consisting of water, food and a radio, and contacted the Tongan Navy to arrange for their rescue later that afternoon.

"We are very pleased with the successful outcome of this mission and for the survivors to be reunited with their family," he said.

"Christmas is about being with your loved ones so I am sure this news is a great relief to their family, friends and community.

"Although we are thousands of miles away from those who need help, we remain ready to assist our Pacific neighbours if required."

The Orion left Whenuapai at 8.45am today to scour an initial search area of about 3000 square nautical miles off Tongatapu, the largest of Tonga's three main island groups.

The Rescue Co-ordination Centre New Zealand sought the NZDF's assistance, Webb said.

The men were being interviewed by Tongan police and the RCC was due to receive a report on that tomorrow afternoon.

The mission to Tonga is the 12th search and rescue operation undertaken by the NZDF in the Pacific since January.

The Air Force's NH90 medium utility helicopters and the P-3K2 Orion surveillance aircraft have flown more than 210 hours on 17 search and rescue missions in New Zealand and the Pacific since January. This represents a 44 per cent increase on the 147 flying hours recorded for 2015.

Missions to the Pacific account for about 87 per cent of total hours flown on search and rescue operations this year.