Studies performed by several Brazilian institutions concluded that liquefied natural gas (LNG) could be the best fuel to generate electric power in some non inter-linked networks in the Brazilian Amazonas Region. Based on this assumption, a non-linear model was developed to optimise the LNG supply for such systems in the State of Para. Some properties of the problem allowed a successive linearisation strategy to solve it. The results obtained show that the proposed model is very efficient for optimising LNG supply systems in such cases.