The brigade moved to Greta in October 1941 and was mobilised their for full time service following Japan's entry into the war. At this time, the 14th Brigade relieved the 1st Brigade in Newcastle, to allow that formation to undertake further collective training. The invasion never came and in May 1942, the brigade – consisting of the 3rd and 36th Battalions and the recently delinked 55th – was sent to Port Moresby to bolster the garrison there. At the time, the brigade was assessed as being only partially trained. The 3rd Battalion undertook defensive duties around Port Moresby initially, but was later committed to the fighting along the Kokoda Track in September and October 1942 undertaking patrols and taking part in several actions including the Battle of Ioribaiwa, the Second Battle of Eora Creek – Templeton's Crossing and the Battle of Oivi–Gorari. Later, the battalion was committed to the assault on the Japanese beachheads around Buna–Gona.