Hong Kong is the world's most expensive city for expats, leapfrogging Angolan capital Luanda in the annual chart compiled by consultancy firm Mercer.

Luanda, which had consistently topped the list in recent years, fell in the ranking owing to the weakening of its local currency.

Zurich and Singapore were third and fourth on the list, unchanged from a year ago. Tokyo rose to fifth.

The survey is designed for companies to calculate expat workers' allowances.

It weighs up the cost of living in 209 cities across the world, comparing the cost of more than 200 items in each location, including housing, transport, food, clothing and entertainment.

Hong Kong The world's most expensive city 12077 $US rent for a 3-bedroom house 128 $US for a pair of jeans

7.8 $US for a cup of coffee

4.8 $US for a hamburger meal

1.2 $US for a small imported beer AFP

Kinshasa was ranked sixth, appearing in the top 10 for the first time, followed by Shanghai, Geneva, N'Djamena, and Beijing.

'Volatile'

Mercer said that rankings were affected by "volatile markets and stunted economic growth in many parts of the world".

The world's least expensive cities for expats, according to the cost of living survey, is the Namibian capital Windhoek, followed by Cape Town.

What's the rent? For a 2-bedroom apartment, no furniture, good neighbourhood 6809 $US Hong Kong 6700 $US Luanda

5100 $US New York

4583 $US London

4200 $US Moscow AFP

In the UK, London dropped five places to 17th, Aberdeen fell seven places to 85th and Birmingham, in 96th, dropped by 16 places. Further down the list, Glasgow dropped 10 places to 119th and Belfast was down three places to 134th.

A survey earlier this year, by the Economist Intelligence Unit (EIU), ranked Singapore as the priciest city in the world ahead of Zurich, Hong Kong, Geneva and Paris.