Tokyo remains the most expensive city in Asia for expatriates, while Singapore overtook Hong Kong to become the costliest place in the region outside of Japan, according to a survey by human resources consultancy Mercer.

Tokyo retained its status as the second most expensive city in the world for expatriates after Luanda in Angola, which topped the list for the second year in a row.

Osaka in western Japan was the next most expensive Asian city, ranked sixth in the world, followed by Singapore at the world's number eight and Hong Kong at number nine.

'Most Asian cities have moved up in the ranking as availability for expatriate accommodation is limited and demand is high,' senior researcher Nathalie Constantin-Metral at Mercer said in a statement.

The increase in cost of living was, however, most keenly felt in Australia due to a rise in the Aussie against the US dollar, Mercer said in its 2011 Cost of Living survey.

Sydney rose 10 places to rank 14th, while Melbourne jumped to 21st from last year's 33th position.

London fell to 18th from 17th, while New York dropped to 32nd from 27th. – Reuters