A number of analysts have identified the 1986 South Pacific Nuclear Free Zone (SPNFZ) Treaty as one of Australia's major achievements in the area of arms control diplomacy. This article challenges the orthodox view in the secondary literature that Australia's pursuit of a SPNFZ Treaty was motivated exclusively by a desire to protect the nuclear dimension of its alliance relationship with the United States from more ‘radical’ proposals in the region. Drawing on previously unreleased documents made available to the author by the Department of Foreign Affairs and Trade under the Commonwealth's Freedom of Information Act, this article argues that the Hawke government's pursuit of a nuclear‐free zone in the South Pacific was motivated primarily by what it perceived as an opportunity to promote Australia's image as an activist middle power committed to bolstering the coherence of the global non‐proliferation regime.