New Zealand Defence Force investigates after Manawanui fuel leak reported

In partnership with Samoan officials, the New Zealand Defence Force (NZDF) deployed personnel and commissioned a Samoan company to dive on the wreck of HMNZS Manawanui on Friday 20 February, after being made aware of the report earlier in the week.

No evidence of a leak or sheen was found.

Captain Rodger Ward RNZN, HMNZS Manawanui Response Lead, says the NZDF takes its responsibilities on this issue very seriously.

“Water samples have been taken and will be analysed, and further monitoring of the site is being carried out as a precaution,” he says.

“The salvors hired to pump the fuel and other pollutants from the ship following the sinking were very thorough in searching all tanks as well as compartments that could likely contain fuel.

“In March 2025 at the conclusion of salvage work to remove diesel fuel and other pollutants, we advised that there may be a very small amount of residual fuel remaining somewhere in the vessel.

“An NZDF engineering report concluded that if there was fuel remaining on the vessel it would be trace amounts only, and if any escaped it would likely quickly disperse through wind and wave action.”

He says the absence of a sheen and any evidence of a leak suggests there was either an intermittent discharge of trapped fuel from a pump or pipe, or the sheen originated from another source such as a passing vessel.

“Events such as this will occur from time to time as the wreck settles and begins to degrade and as traffic in the vicinity of the wreck begins to normalise.”

HMNZS Manawanui sank off the coast of Samoa on 6 October 2024 after running aground on a reef the previous evening.