Hong Kong is the overall most expensive in Asia-Pacific and is the second most expensive city in the world (after Luanda).
Singapore is the second most expensive city in the Asia-Pacific region for expatriates (4th most expensive in the world) and tops the region rankings when costs related to housing, education, medical and transport are excluded.
http://www.xpatulator.com/cost-of-living-article/Asia-Pacific-Expat-Cost-of-Living-Comparison_709.cfm