SYDNEY - A 57-year-old Tongan man, who has been hailed a real-life Aquaman for surviving 27 hours at sea after Saturday's (Jan 15) devastating tsunami struck his island, said he went under nine times before latching on to a log and making it to safety.

"On the eighth time, I thought the next time I go underwater, that's it, because my arms were the only things that were keeping me above water," said Mr Lisala Folau, who is disabled and cannot walk properly, speaking to Reuters from Tonga's capital, Nuku'alofa.

"So the ninth time I went under... I came up and grabbed a log. And that's what kept me going."

The eruption of the Hunga Tonga-Hunga Ha'apai volcano killed at least three people and sent tsunami waves rolling across the Tongan archipelago, damaging villages and resorts and knocking out communications for the nation's 105,000 people.

Mr Folau, who lived on the isolated island of Atata, with a population of about 60 people, was swept out to sea at around 7pm on Saturday.

He had climbed a tree to escape a first wave but when he got down, another big wave swept him out.

"I could hear my son calling from land but I didn't want to answer my son because I didn't want him to swim out to find me," said Mr Folau.

"The waves kept twirling around here and there... What came to mind is, at sea, there is life and death. Until you reach the shore, then you know if you are alive or dead."

Mr Folau said he slowly managed to swim 7.5km to the main island of Tongatapu, reaching the shore 27 hours later at about 10pm on Sunday.

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His heroics have gone viral on social media, with one Facebook post calling him a "real-life Aquaman", referring to the comic book and film character.

When asked if he knew who Aquaman was, Mr Flolau said he did not.

Reuters was unable to independently verify the events.

Atata, about 8km north-west of Nuku'alofa, or a 30-minute boat ride, has been almost entirely destroyed in the tsunami that hit the islands.