The cities of the Asia-Pacific region dominate the list of the most expensive places in the world for expats to live, accounting for 18 of the priciest cities on the planet.

The unwanted prize for the most expensive city in the world went to Luanda, the capital of Angola, for the second straight year.

Luanda sits atop the cost tree due to its high number of oil workers and the nation’s reliance on imports, according to the annual study by Mercer.

Angola’s capital Luanda retained the unenviable title of the world’s most expensive city for expatriates, narrowly edging out Tokyo, according to a new survey.

The Mercer group‘s study named the Pakistani port Karachi as the least expensive city, with living around three times cheaper than in Luanda.

Oil-rich Angola is a magnet for foreign workers who push up already high prices inflated by a reliance on imports.

Luanda in Angola is the world’s most expensive city for expatriates, according to the latest Cost of Living Survey from Mercer.

For the first time, three African cities – Luanda, Ndjamena and Libreville in Gabon (7) – were among the 10 most expensive cities.

The top ten also includes three Asian cities; Tokyo (2), Osaka (6) and Hong Kong (jointly ranked 8).

Moscow (4), Geneva (5) and Zurich (joint 8) are the most expensive European cities, followed by Copenhagen (10).

Vienna is the best city in the world to live, a survey said Wednesday, putting Europe at the top of the rankings with Asia and Africa trailing.

The Austrian capital “retains the top spot as the city with the world’s best quality of living,” British consultancy firm Mercer said in its 2010 Quality of Living Survey.

Swiss cities Zurich and Geneva followed in second and third places respectively, while Vancouver in Canada and Auckland in New Zealand were joint fourth.

In Mercer Consultings annual Quality of Living Survey, Europe once again dominates the list of 215 countries around the world.

The top three cities are, by rank, Vienna, Zurich (last years winner), and Geneva.

Commonwealth nations fare pretty well, too, winning 9 of the top 30 spots, even though London comes in only at 38.

Mercer has just released its top 50 most expensive cities in the world based on cost of living.

Mercer’s Worldwide Cost of Living Survey 2008 is used to help multinational companies and governments determine living costs for their expatriate employees, who usually demand a relatively high quality of life.

Mercer’s survey covers 253 cities across six continents and measured the relative cost of over 200 items in each place, including housing, transport, food, clothing, household goods and entertainment.