Vanuatu's patrol boat RVS Takuare remains docked at the SinoVan wharf in Port Vila where it has been since the second week of June because of an engine defect.
The Maritime Commander Colin Ioan Kalwatman said the engine of the Australian-supplied vessel ship was producing carbon monoxide, and black smoke could be seen on the covering of the exhaust.
The commander said he didn't want to risk continuing using the Takuare because the emissions could harm the team in the engine room.
The boat's chief engineer Wesley Sogarie said as the boat was under warranty, he was awaiting engineers from Australia for further investigations.
Australia's Department of Defence advised countries which had been gifted Guardian-class patrol boats of an issue with the main engine exhaust system.