Formerly known as the Pacific Three Closer Economic Partnership (P3 CEP), negotiations were launched by the President of Chile and the Prime Ministers of New Zealand and Singapore at the APEC Leaders Summit in 2002. Brunei Darussalam asked to join the negotiations as a founding member before the final round of negotiations in April 2005.
Ministers from Brunei, Chile, New Zealand and Singapore announced the successful conclusion of negotiations of a Trans-Pacific Strategic Economic Partnership Agreement (Trans-Pacific SEP) at the APEC Trade Ministers meeting in Jeju, Korea on 3 June 2005. As part of the overall package, Ministers also announced the conclusion of negotiations on a binding Environment Cooperation Agreement and a binding Labour Cooperation Memorandum of Understanding.
Representatives from New Zealand, Chile and Singapore signed the Trans-Pacific SEP and accompanying Labour Cooperation MOU and Environment Cooperation Agreement in Wellington on 18 July 2005. Brunei Darussalam signed the agreement in Wellington in early August 2005.
The Trans-Pacific SEP, Labour Cooperation MOU, Environment Cooperation Agreement, along with a National Interest Analysis, were submitted to the New Zealand Parliament under the Parliamentary treaty examination process on 18 July 2005 and referred to the Foreign Affairs, Defence and Trade Select Committee.
New Zealand and Singapore deposited instruments of ratification on 20 and 28 April 2006 respectively. The agreement provisionally entered into force (between New Zealand and Singapore only) on 1 May and officially entered into force on 28 May. The Agreement entered into force for Brunei on 12 July 2006, and for Chile on 8 November 2006.