A New Zealand Defence Force frigate has come to the aid of a yacht in the north Tasman Sea.

The yacht, skippered by a 78-year-old man, was on a two-week sailing trip out of Brisbane.

Crew from HMNZ Te Kaha approach the stricken vessel Mahi in the north Tasman Sea. Photo: Supplied.

Commander (CDR) Simon Griffiths, Commanding Officer of HMNZS Te Kaha, says the yacht Mahi got into difficulty recently when it suffered a leak around its rudder stock and started to take on water.

The yacht's skipper activated the boat's emergency beacon, and Australia's Joint Rescue Coordination Centre picked up the distress call and relayed it to vessels in the yacht's vicinity.

Te Kaha, which is sailing to Southeast Asia to participate in an international maritime warfare exercise, was around 180 nautical miles south of the yacht when she received the distress message.

The stricken vessel was drifting around 490 miles east-north-east of Brisbane and 250 miles southwest of Noumea at that time.

CDR Griffiths says the ship raced towards the yacht's location at best speed soon after they received the message.

The frigate's Seasprite helicopter was launched to locate the yacht and establish communications with its skipper.

Once Te Kaha arrived on the scene, a team of three personnel including an engineer and a medic visited the stricken vessel using one of the frigate's rigid hull inflatable boats.

'What was supposed to be a two-week trip for the skipper had turned into five weeks,” explains Simon. 'During that time, the yacht had been both becalmed and battered by storms.

'The yacht's two masts were damaged during the storm and it was down to its last set of useable sails.

'By the time our team got on board, the skipper had run out of food, though he managed to get the leak under control.

'Our engineer managed to repair the leak. We also stocked him up with 10 days' worth of food including military ration packs, fruits, milk and even some Weetbix and Marmite. We also filled his fuel tanks with 80 litres of diesel.”

The ship's medic also checked the yacht's skipper.

'Despite his recent ordeal, he was in good health and very good spirits,” he adds. 'He was extremely grateful for the assistance we gave him and was confident he could now get himself and his yacht back to Brisbane.”

Te Kaha provided the skipper with the latest weather forecast and information from Joint Rescue Coordination Centre before leaving the yacht.