 The 55th Infantry Battalion's companies were already badly afflicted by malaria and other tropical diseases, and were withdrawn and sent back to Port Moresby in early August, but the garrison was further reinforced with Second Australian Imperial Force troops of Brigadier George Wootten's 18th Infantry Brigade of the 7th Division, which began arriving on 12 August, although it would not be complete until 21 August. This veteran brigade, which had fought in the Siege of Tobruk earlier in the war, consisted of the 2 / 9th, 2 / 10th and 2 / 12th Infantry Battalions. Anti-aircraft and artillery support was provided by the 9th Battery of the 2 / 3rd Light Anti-Aircraft Regiment, the US 709th Anti-Aircraft Battery and the 9th Battery of the 2 / 5th Field Regiment, while various signals and logistics troops provided further support.
