Mr Samu described the terrifying ordeal his young family faced on Saturday as they struggled to escape powerful 300km/h winds and neck-high water that rose across the island.
He said the family had been told to leave their home and move to another place to sit out the storm.
"We thought we would only be affected by strong winds. When we were in that house waves began to rush into the village. When the winds began to rise, we ran for safety," he said.
He and wife Mereani Biukula tried to flee to higher ground as seas began to slam the coastline and destroy everything in their path.
"When we got to the other side, the water level was up to my neck. The house began to fall and waves began to pound on us, we drowned in the waves, our son was above water and he then drowned but we managed to save him."
Mr Samu said he held on to his son but the waves swept the child and his wife from his grasp.
His wife was later found washed up alive on the other side of the village.
Eight people died on Koro Island, which was directly in the path of Cyclone Winston.
The death toll stands at 29 and 89 people are being treated for injuries.
How to donate
• Red Cross: redcross.org.nz
• Tear Fund: tearfund.org.nz
• World Vision: worldvision.org.nz
• Unicef: unicef.org.nz
• Oxfam: oxfam.org.nz
• Habitat for Humanity: www.habitat.org.nz
