A dredger partially sank while anchored off Middle Park Beach in Port Phillip in Melbourne, Australia, overnight (local time) into Sunday, November 8.
Kirra had been supporting the City of Port Phillip's Middle Park Beach renourishment project. Nobody was aboard the vessel when the incident occurred and no injuries were reported.
Parks Victoria said the pollution boom surrounding the vessel was containing a small diesel release. Containment and recovery operations are continuing.
The agency is coordinating the response with Environment Protection Authority Victoria (EPA), the Victoria Department of Transport and Planning, the City of Port Phillip, and other agencies. They are working to salvage and remove the dredger "as soon as practicable".
The council said the cause of the incident is not yet known.
South Melbourne Beach has been closed between South Melbourne Surf Life Saving Club and Kerferd Road Pier, and people have been advised not to enter the water there.
The council said the closure was set north of the project site in light of where the incident occurred and the tidal conditions.
The closure remains under review.
EPA advice covering Middle Park Beach and Port Melbourne Beach urges people and pets to stay clear of the water if it appears oily, is discoloured, or has a chemical smell. A notice to mariners has been issued warning of possible floating or submerged hazards.
Mariners have been advised to avoid the vessel's immediate vicinity.
Hall Contracting moved Kirra and support vessels from Anderson Inlet to Port Phillip in September for the works.
As part of the project, about 30,000 cubic metres of sand will be dredged from a location approximately 750 metres offshore, then pumped onto the beach. Completion is scheduled for December 18, ahead of the summer peak.