Sago palm is an emerging crop for starch production which is predominately found in southeast Asia. Its expansion has potential danger to ecologically sensitive terrestrial ecosystems. This work aims to provide expansion strategies for sustainable sago plantation expansion based on the increase in sago starch demand. Mathematical optimisation model of the class linear programming is developed. The total land area available for expansion under the different land types is considered. The developed model determines the optimised area under each land type to be used for sago plantation expansion based on the trade-off between expansion cost and carbon emissions. The results show that the annualised expansion cost and the annual carbon emission that is inevitable to meet the expected demand is 1.15 M USD and 4.25 t CO2-eq/ha/y.