[3] In 1938, the Australian Commonwealth Naval Board (ACNB) identified the need for a general purpose 'local defence vessel' capable of both anti-submarine and mine-warfare duties, while easy to construct and operate.

[8] The need for locally built 'all-rounder' vessels at the start of World War II saw the "Australian Minesweepers" (designated as such to hide their anti-submarine capability, but popularly referred to as "corvettes") approved in September 1939, with 60 constructed during the course of the war: 36 ordered by the RAN, 20 (including Ballarat) ordered by the British Admiralty but manned and commissioned as RAN vessels, and 4 for the Royal Indian Navy.

[3] On 1 November, she was given the duty of providing anti-submarine protection to converted ocean liner Queen Mary, prior to her departure as part of a troop convoy to the Middle East.

[3] On 14 February, Ballarat carried out one of the largest rescue operations in the region, collecting 215 survivors from the torpedoed merchant vessel MV Derrymore.

[3] In 1945 she returned to Sydney to perform minesweeping operations prior to the arrival of the British Pacific Fleet, and then participated in the invasion of Okinawa.

[3] Ballarat was present in Tokyo Bay on Victory over Japan Day (2 September 1945), when the Japanese Instrument of Surrender was signed.