 By then, the Allies had reinforced New Guinea with additional troops (primarily Australian) starting with the Australian 14th Brigade which embarked at Townsville on 15 May.The added forces slowed, then eventually halted the Japanese advance towards Port Moresby in September 1942, and defeated an attempt by the Japanese to overpower an Allied base at Milne Bay.In the meantime, the Allies learned in July that the Japanese had begun building an airfield on Guadalcanal.