Watch: Dramatic helicopter rescue from sinking boat

A New Zealand rescue helicopter has made a dramatic rescue by saving three sailors from a sinking boat.

Early on Sunday, three people set off from the South Island port town of Lyttleton on a long voyage up the east coast to the North Island town of Whangamata.

"They had just bought the boat and was their first trip on it," a spokesperson for Life Flight's Westpac Rescue Helicopter says. "They had life jackets but no working radios."

Unfortunately, the amateur sailors ran into trouble and were forced to set off a distress beacon about 40 nautical miles east of the Clarence River.

At around 9am the Life Flight's Westpac Rescue Helicopter was alerted and sent on a life-and-death mission.

They discovered the stricken vessel drifting in large seas estimated to be between six to eight metres tall. The boat had no power and was taking on water and sinking.

A paramedic went into the water and swam to the boat and prepared those on board for rescue. All three were successfully winched on board and transported to Wellington Hospital for treatment.

"Without their distress beacon there is no way we would have found them," the spokesperson says.

"Chances are very high they may not have survived, judging by the sea state and a boat with no working engine."

Newshub.