Hong Kong - Asia will have the world's largest number of millionaires as early as next year despite the expected tapering of the US Federal Reserve's stimulus programme, according to a report published yesterday.

With strong growth and high saving rates, the wealth of the region's millionaires will grow by an annual average 9.8 per cent and reach nearly US$16 trillion (S$20 trillion) in 2015, according to the wealth management unit of Royal Bank of Canada.

Despite concerns of devaluing asset prices due to capital outflows triggered by Fed tapering, Asia is set to lead the world in the number of millionaires and their total wealth, the bank said in a report prepared with consulting firm Capgemini.

"The region's high net worth population and wealth has increased by 31 per cent and 27 per cent respectively since 2007, far outpacing growth in the rest of the world of 14 per cent and nine per cent," George Lewis, group head of RBC Wealth Management, said in a statement.

The number of millionaires in Asia surged by 9.4 per cent year-on-year to 3.68 million in 2012, still trailing North America's 3.73 million.

Millionaires in the report are defined as individuals with investable assets of US$1 million or more, excluding residence, collectibles and others.

Hong Kong topped its Asian peers in the growth of both millionaire numbers and their investable assets in 2012.