Singapore has been ranked as the fourth most costly destination in Savills' World Cities Review report, with the average value of luxury homes in the country increasing 144 percent over the past five years.

"Singapore has the highest concentration of millionaire households in the world (16 percent with US$1 million plus), and the capacity to buy residential property is obviously high," said Savills.

Home values of the super-rich in the top 10 cities worldwide climbed 10 percent in the first six months, according to the report, higher than the average price growth of six percent for ordinary properties in similar cities and lower than the 65 percent growth in ultra-prime properties over the past five years.

Since 2005, the price growth of ultra-high-value homes has been the highest in the emerging "new world" economies of Singapore at +144 percent, followed by Mumbai at +138 percent, Moscow at +110 percent and Hong Kong at +83 percent. This pattern reflects the geography of the new wealth generation, as well as the creation of new billionaires over that period.