The Russian city of Moscow was the most expensive major city on earth in March of this year, a position it has retained since last being surveyed a year before, according to Mercer, the consulting firm.

According to its Cost of Living Index, Moscow has a figure of 142.4, down slightly from its 134.4 figure in March 2007 but still keeping it ahead of the 143 cities in the survey.

Russia's economy has been buoyed by the surge in wealth linked to the rise in the price of oil and natural gas, as well as for other commodities - such as gold - that the vast nation produces. The rising wealth has prompted a substantial rise in the level of spending and demand for assets such as property in cities such as Moscow.

The second most expensive city was Tokyo in Japan, with a reading of 127, up from 122.1, while in third place was London, at 125. London fell to third from second most expensive city last year. At the other end of the scale, the cheapest city was Asuncion in Paraguay, with an index level of 52.5.

The indices are based on Mercer’s cost of living database and are adjusted to include rental accommodation costs.

Among other figures, Oslo, in Norway, is the fourth most expensive city, at an index figure of 118.3, followed by Seoul, South Korea, at 117.7.