Between 1946 and 1975, the Secretary of External/Foreign Affairs also served concurrently as the Permanent Head of the Prime Minister's Department. For much of this period, several New Zealand Prime Ministers including Peter Fraser, Walter Nash, and Keith Holyoake held the External Affairs portfolio. MFAT had no relation to an earlier Department of External Affairs, which was responsible for administrating New Zealand's South Pacific island dependencies of Niue, the Cook Islands, Tokelau, and Samoa between 1919 and 1943.
Between 1946 and 1975, the Secretary of Foreign Affairs concurrently served as the Head of the Prime Minister's Department. This period saw several New Zealand Prime Ministers, including Peter Fraser, Walter Nash, and Keith Holyoake, holding both roles. The Ministry for Foreign Affairs (MFAT) was established after the earlier Department of External Affairs, which managed New Zealand's South Pacific island dependencies from 1919 to 1943.