As far as ISD was concerned it was used as a wireless relay station for the New Guinea Section. The site was selected by Commander Roy Kendall, the head of SIA and was about inland from the town of Cairns, North Queensland. The site was originally chosen for its good radio reception. There were, however, good security conditions for training, until the Cairns district became a very active assembly area for Australian and US troops operating in New Guinea. ZES was closed down in December, 1945 and the property disposed of by the Australian Government in 1950.