The Maritime Administration of the Transport Ministry in Tonga is confident oil leakages from several sunken vessels in Nuku'alofa have been contained.
Up to 20 boats have been abandoned for various reasons in Faua Harbour including about three vessels that have become submerged and are leaking oil.
A Senior Marine Environment Officer Kelela Tonga says she was informed of the oil spills over a week ago and says the Port Authority has been given instruments to prevent the oil from spreading.
"I can say it's very successful because there's no further spill from the source. And Port Authority people have been trying to get rid of the oil onboard these vessels."
Kelela Tonga says the oil leaks spread to an area of 15 metres in diameter and she is confident it is posing no threat to the environment.