The South Pacific Nuclear Free Zone (SPNFZ) Treaty was signed at the meeting of the South Pacific Forum (SPF) in 1985. The treaty was a fruit of SPF's regional cooperation on the nuclear issues, which started at the formation of SPF.However, the situation on the nuclear issues has dramatically changed since the signing of the SPNFZ Treaty. One change is the effect of the end of the Cold War, which contributed to strengthen nuclear non-proliferation regime. In compliance with the Comprehensive Nuclear Test Ban Treaty (CTBT), which was signed in 1996 as a part of nuclear non-proliferation regime, France ended its nuclear testing in the Pacific and signed the protocols of the SPNFZ Treaty, which it used to refuse to sign. The effect of the end of the Cold War also led to the proliferation of nuclear weapon-free zones in the world.Another change is the emergence of new nuclear problems for SPF. One issue is the clean-up and compensation for the ex-nuclear testing sites in the Pacific. The second is the plans of constructing nuclear wastes storage sites in the Pacific. The third is the shipment of plutonium and nuclear wastes across the Pacific, which has been conducted by the Japanese government.SPF has responded to these changes by both regional and interregional approaches. In particular, it is noteworthy that SPF has sought for cooperation with other nuclear weapon-free zones in the Southern hemisphere in the Review Conference of the Parties to the Non-Proliferation Treaty (NPT) as an interregional approach. Whether SPF will change its stance from tackling only regional nuclear problems to playing a role for global nuclear disarmament depends on the realization of the Southern Hemisphere Nuclear Weapon-Free Zone.