Three teenage boys have been rescued after drifting in the Pacific Ocean for 50 days in a small boat, according to news reports.

The three, who disappeared from New Zealand's Pacific territory of Tokelau on October 5, were presumed to have drowned after unsuccessful searches by the New Zealand air force.

A memorial service was held for the two 15 year olds and the 14-year-old.

Radio New Zealand International reports the boys were rescued yesterday by a New Zealand tuna boat that spotted them north-east of Fiji.

The ship's first mate, Tai Fredricsen, told the radio program the three boys were in reasonably good spirits considering they had been adrift for close to two months.

"They were very badly sunburned, but really, they just needed basic first aid, which was some creams just to help soothe their burns," he said.

He said the boys were able to drink, "which was quite amazing considering how long they were without food for".

He said the boys drank rainwater during their time adrift.

"They said they had last eaten almost two weeks prior to us rescuing them," he said.

Mr Fredricsen says the only food they had was one seagull that they managed to catch and eat raw.

"They said they had last eaten almost two weeks prior to us rescuing them," he said.

"Somehow, we're still trying to work out how, they actually caught a sea bird which actually landed on their very small craft and they were able to eat that which was a very good decision."

The ship, which is on its way back to New Zealand, is expected to leave the boys at the Fiji capital, Suva, on Friday, when they will be checked at a hospital.

- ABC/AAP