In mid-August 1942, the 2/27th battalion was deployed to New Guinea, where the Japanese were threatening to capture Port Moresby, following a landing around Buna in July. After initially being kept back at Port Moresby in reserve as the Battle of Milne Bay was fought, in early September 1942, at the height of the Kokoda Track campaign, the 2/27th moved north towards the Kokoda Track, joining Brigadier Arnold Potts' Maroubra Force. Following delaying actions around Isurava, the Australians had been forced to withdraw further south along the track, and in an effort to stem the Japanese advance, on 6 September the 2/27th, as the freshest of the 21st Brigade's units, was committed to the fighting, taking up a defensive position at Mission Ridge, on the northern face of Brigade Hill. For the next two days, the battalion held off a frontal attack by a Japanese battalion, but as a result of flanking moves a withdrawal to Menari was ordered and the 2/14th and 2/16th Battalions withdrew, leaving their wounded with the 2/27th, who formed the brigade rearguard. After 'B' and 'C' Companies launched a brief, but successful local counterattack, the 2/27th was also able to break contact. With the Japanese pressing hard, Potts ordered a further withdrawal from Menari before the 2/27th arrived, effectively cutting it off from the rest of the brigade. For the next two weeks, the 2/27th fought through the jungle, carrying their wounded with them, to regain contact with supporting units, eventually linking up with them at Jawarere on 22 September.