In early 1944 5MWS became part of a force of RAAF and United States Army aviation engineer units which were selected to build airfields at Aitape in New Guinea from which air support would be provided to Allied operations around Hollandia after US Army forces landed there on 22 April. 5MWS departed Melbourne on 15 February, and eventually joined up with the main body of the airfield engineer force at Lae on 1 April where it received training in infantry tactics. The Landing at Aitape took place on 22 April, and 5MWS came ashore the next day. The airfield at Aitape was ready to be used from 25 April and was later expanded by the aviation engineers. On 6 July 5MWS landed on Noemfoor Island where it again formed part of an aviation engineer force tasked with repairing and expanding the island's airfields. Allied forces had first landed on the island on 2 July, and it was still not secure when construction work began. As a result, 5MWS personnel were required to man perimeter defences, during which they captured 12 Japanese personnel. While at Noemfoor 5MWS was redesignated No. 5 Airfield Construction Squadron (5ACS) on 18 July. As at 25 November, No. 4 Airfield Construction Squadron and 5ACS were the main units of No. 62 Wing. This wing formed part of the Australian First Tactical Air Force, which was the RAAF's main mobile force.