This paper re-kindles the debate on the feasibility of a Pacific Islands currency union in view of the recent expansion and consolidation of regional strategies and agreements such as the 'Pacific Plan' and the Pacific Agreement on Closer Economic Relations Plus. These initiatives, including past efforts, have given limited consideration to the subject for a Pacific Islands currency union. This study exploits the optimal currency area theoretical framework and employs the Gonzalo and Ng (2001) decomposition method. This is the first time this method is used in the analysis relating to currency or monetary unions. Newly-constructed quarterly time series data are also applied. This paper investigates the dynamic effects of permanent and transitory shocks on key macroeconomic variables among Pacific Island countries (PICs). Evidence shows that the proposed union of six PICs (Fiji, PNG, Samoa, Solomon Islands, Vanuatu and Tonga) do not meet most of the preconditions for a union. However, further investigation shows evidence for the Melanesian countries (Fiji, PNG, Solomon Islands and Vanuatu) to possibly form a monetary union, preferably with the Australian dollar as the anchor currency. Nonetheless, further costs in terms of the alignment of policies by Melanesian countries are required.