Wilder-Neligan's initial role was as a deputy district officer for the garrison of Rabaul on the island of Neupommern (later renamed New Britain). In May 1921, when the military administration of the former German colony was handed over to an Australian civil one mandated by the League of Nations, he was transferred to the administration of the newly created Territory of New Guinea as district officer for Talasea in west New Britain. Early in January 1923, the Administrator, Evan Wisdom, summoned him to Rabaul to answer allegations of financial malpractice that had been made against him by a former German planter. It appears that he resigned and sailed for Rabaul. Going ashore to rest for a few days at the village of Ekerapi before continuing his journey, he died during the night of 9/10 January. Survived by his wife and daughter, he died intestate and with debts.