Following World War II the Royal Australian Navy (RAN) was required to clear naval mines from the waters around Australia and New Guinea.

During World War II both the Allies and Japanese laid mines in Australian and New Guinean waters.

[2] Ships involved included HMAS Swan, Ararat, Cowra, Deloraine, Echuca, Katoomba, Lithgow, Mildura and Warrnambool as well as harbour defence motor launches 1323, 1328, 1329 and general purpose vessels 960 and 963.

[4] On 13 September 1947 Warrnambool struck a mine off North Queensland which had been laid by Bungaree in November 1943 and sank shortly afterwards with four sailors killed and another 25 wounded.

Some of the awards were delayed and others never granted, however, due to disagreements between the RAN and the Government over whether post-war minesweeping constituted 'operational' service.