He led Australia's delegations to many United Nations conferences including the ILO, WHO, UNCTAD, and ECAFE; he also led Australia's delegation to the Third United Nations Conference on the Law of the Sea which resulted in the adoption of a wholly revised Convention on the Law of the Sea.
He was appointed as Australia's Ambassador to Belgium and the European Community from 1965 to 1968; to South Vietnam during the war years of 1968 to 1970; to the Federal Republic of Germany from 1971 to 1975; to the United Nations as Australia's permanent representative from 1975 to 1978.