The Asia-Pacific region has the highest number of millionaires in the world, having overtaken North America for the first time, according to the Capgemini World Wealth Report.

In 2011, the Asia-Pacific region recorded an increase of 1.6 per cent to 3.37 million high net worth individuals (HNWI), those with US$1 million or more in investable assets, excluding their home.

North America was a close second with 3.35 million HNWIs.

But North America is still larger than the Asia-Pacific region in terms of HNWI total wealth, representing 11.4 per cent of total HNWI wealth of $42 trillion compared to 10.7 per cent for the Asia-Pacific region.

"We predicted last year that we would overtake North America. That has happened, but not fully," Capgemini wealth management specialist Dorus van den Biezenbos said.

"We have overtaken North America in numbers, but not in wealth."

Van den Biezenbos said he expected to see more volatility of markets, but predicted the Asia-Pacific region would overtake North America in HNWI wealth as well in 2012.

"We will overtake North America on both accounts," he said.

The total number of HNWIs in Australia fell by 6.9 per cent to 179,5000, largely due to a decline in the local stock market, lower real estate prices and a decrease in household savings.

Ultra high net worth individuals, those with more than US$30 million in investable assets, suffered the steepest decline in wealth.

"They invest traditionally in more risky and less liquid investment, because they can afford to. But it meant they couldn't get their money out in time," van den Biezenbos said.

It was the first time Capgemini produced the report in partnership with the Royal Bank of Scotland Wealth Management.