Even after the tremendous efforts of World War II, Army activity continued at a high level for several years. Following agreement reached within the British Commonwealth and with the United States, a British Commonwealth Occupation Force (BCOF), comprising Australian, British, Indian and New Zealand formations, was raised and deployed to participate in the occupation of the defeated Japan. Its main tasks were demilitarisation and demobilisation, as well as enforcing military government regulations. Because of the Australian commitment in the Pacific theatre of the war, the appointment of GOC BCOF was filled by Australian Army officers. The Australian Army’s contribution was the 34^th Infantry Brigade (three battalions - 65^th, 66^th and 67^th). This formation was raised at Morotai, and drawn from infantry units spread across the South West Pacific Area at the cessation of hostilities. An armoured car squadron and a general hospital, along with other smaller units, were also contributed.¹²⁹

Two years later the bulk of the Commonwealth’s Forces had been withdrawn, but Australia still maintained her presence in Japan. The three battalions of 34^th Infantry Brigade were the nucleus of the post-war Regular Army and were designated 1^st, 2^nd and 3^rd Battalions of the Australian Regiment in 1948, and the Royal Australian Regiment (RAR) in the following year. Of the original three battalions, only the 3^rd Battalion (3RAR) remained in Japan.¹³⁰ A 4^th Battalion, (4RAR), was raised in Australia as a depot battalion in 1952 but disbanded at the end of the decade.¹³¹ The occupation of Japan ended with the signing of the Treaty of San Francisco in September 1951.¹³²

To augment the Regular Army of 19,000, the field force component of which was a regular brigade group plus an armoured element, the Citizen Military Forces (CMF ).were re-raised in 1948. The CMF was to comprise two infantry divisions and other units, to a strength of 50,000. However by 1949-50 the CMF strength was only some 23,000.¹³³

Meanwhile, in 1947, the Australian Army's involvement in multinational peacekeeping had commenced, with the contribution of military observers to what was (initially) titled the United Nations Good Offices Commission (GOC). The Commission was tasked with delineating and supervising the ceasefire between the Netherlands forces trying to re-establish Dutch rule in the East Indies and Indonesian forces fighting for the independence of their new republic. The GOC was later retitled the United Nations Commission for Indonesia (UNCI). Its task ended in 1951. The Australian Army also contributed observers to the UN Military Observer Group in India and Pakistan (UNMOGIP) from 1950 until 1985, and one observer to the UN Commission on Korea (UNCOK) in 1950, although this commitment ceased with the outbreak of the war in Korea in the same year.¹³⁴

In mid-1949, the New South Wales and Queensland coal strike, inspired by militants within the miners' union, saw the federal government move troops into the mines to maintain production. The strike came to an end in August because the railways unions decided to move the coal mined by the Army, leaving the mining union isolated within the trade union movement.¹³⁵

In December 1949 a new government was elected, based broadly on a policy aimed at reducing communist influence at home and its further spread through South East Asia. To achieve this aim it appeared necessary to maintain the confidence of nations in the area against external pressure, to encourage regional security and develop local regional, as well as Australia's, defence capacity. The Government, believing that the army structure was inadequate for this task, introduced the National Service Act in 1951. The Act provided for the compulsory call-up of all 18 year old males, with an obligation to serve 176 days, 98 of which were to be full-time. As a result, by 1956, the CMF strength had reached over 87,000.¹³⁶