The Angolan capital, Luanda, topped the list of the world's most expensive cities for expatriates, followed by Moscow and Tokyo, according to Mercer's 2013 cost of living survey.

Hong Kong, ranked 7th, is the most expensive in China for expatriates, while Shanghai, at 14, ranked costliest among mainland cities.

The survey covered 214 cities and measures the comparative cost of more than 200 items, including housing, transportation, food, clothing, household goods, and entertainment.

Costs vary dramatically. The cost of a cinema ticket is $5.91 in Johannesburg compared to $20.10 in London, and the cost of a cup of coffee in Managua, Nicaragua is $1.54 compared to $8.29 in Moscow.

The cost of expatriate housing is typically the biggest expense for employers, and it plays an important part in determining the rankings. To rent a luxury two bedroom unfurnished apartment for one month in Moscow costs $4,600 a month, or 14 times more than Karachi, Pakistan.

The annual survey is to help companies assess compensation allowances for expatriate employees.