'Real life Aquaman': Tongan man swims 7.5km after eruption and tsunami

Lisala Folau is now known as "real-life Aquaman" after he swam 7.5km from Tonga's Atatā Island to Tongatapu, following the weekend's volcano eruption and subsequent tsunami.

Folau, 57, was reportedly swept out to sea when the tsunami waves from the eruption of Hunga-Tonga-Hunga-Ha'apai hit the island on Saturday and he began a mammoth 28-hour swim to the archipelago's main island.

Lisala Folau (inset) swam for 28 hours from Atataa to Tongatapu in Tonga, about 7.5km, after being swept out to sea following the volcanic eruption of Hunga Tonga Hunga Ha'apai volcano. Photo / Supplied

He reached the shore of Sopu around 10pm on Sunday, after swimming 7.5km.

"He practically crawled towards the road so that he was able to be found," Marian Kupu of media agency Broadcom Broadcasting, based in Nuku'alofa, told 1News.

According to Kupu, the man "drifted away and he was holding on to some of the debris caused by the eruption from the islands".

The man is said to still be in shock after the events of last weekend.

"Even five days later he was very emotional when he was talking and sharing his experience. I saw some scars on him, on his face and his body. He looks very weak given the conditions and everything," Kupu added.

New Zealand is one of the nations aiding Tonga after the eruption and tsunami. The New Zealand Defence Force's Hercules aircraft left Aotearoa for Tonga today, filled with urgent aid supplies, including water containers, temporary shelters and generators.

Two naval ships left on Tuesday with supplies and survey equipment.

Defence Minister Peeni Henare announced today a third navy ship will go tomorrow to help in the relief efforts.

The HMNZS Aotearoa will take up to 250,000 litres of fresh water and relief supplies.

HMNZS Canterbury has not been requested yet, but the New Zealand Defence Force's Commander of Joint Forces, Rear Admiral Jim Gilmour, said it was anticipated her capabilities would be required so the vessel is expected to start loading cargo and head for Tonga by Saturday morning at the latest.

"This will be not an intention of getting in front of permissions or asks from the Kingdom of Tonga, our thinking is it's much better to get the capability 15 miles off the coast of Tonga and be turned around, than to be desperately required and still here in New Zealand."

HMNZS Canterbury should arrive about Tuesday, Gilmour said. It will carry relief supplies, desalination plants, helicopters and engineers.

How you can help: To donate to help the people of Tonga, go to: New Zealand Red Cross.