After close examination of the Allied campaigns of the SWPA, the importance of the Australian infantry brigade as a key combat formation is without question. An examination of the infantry brigade group (jungle) as an intermediate formation commanding infantry battalions and numerous attached units demonstrates the role of an infantry brigade as crucial to the victories in New Guinea and Borneo. The complex terrain of the SWPA islands, which sometimes constrained and at times isolated the brigades, offered these formations the opportunity to evolve.

The Australian Army served in numerous theatres and campaigns throughout World War II, earning distinction and at times facing significant challenges. After Australia declared war on Germany on 3 September 1939, Australians deployed and served in combined Allied armies in Europe, North Africa, the Middle East and Asia.1 Conversely, the Australian Army made up the bulk of Allied ground forces in the South West Pacific Area (SWPA) during the Japanese push south in the months following the attack on Pearl Harbor. After the consolidation of their initial advances, the Japanese extended their area of control and established a perimeter line of defence from the Aleutians in the north to the Gilbert and Marshalls in the south. In 1942–43, Australian troops carried the bulk of responsibility in the fight against the Imperial Japanese Army and Navy in a gruelling battle for the island of New Guinea. Thus, by 1943, the Australian Army was the most experienced Allied force in the Pacific.