The number of dollar millionaires around the world increased by 6% last year, defying the impact of the credit crunch, with the fastest growth in the emerging economies of India, China and Brazil.

There are now 10.1 million people worth more than $1m (£508,000) excluding the value of their main homes, according to the latest World Wealth Report from Merrill Lynch and the consultancy Capgemini.

Developed economies in Europe and North America continued to create millionaires, though the rate of growth slowed significantly from 2006 as the credit crunch and inflationary pressures caused the world economy to falter.

But developing markets, driven by thriving exports of commodities and booming domestic markets, proved to be far more resilient. The number of dollar millionaires in India's red-hot economy grew by 22.7%, China followed with growth of 20.3% and Brazil came next with 19.1%.

As an illustration of the growing buying power of emerging markets and the shifting world order, the report cites General Dynamics, the US engineering group, which sold more Gulfstream jets to overseas buyers than in North America for the first time last year. Ferrari also experienced unprecedented sales to emerging markets. The luxury carmakers' sales in the Asia-Pacific region increased by 47.2% last year, while sales to the Middle East grew by 32.3%. That compared with single-digit growth in Ferrari's traditional markets of the US and Germany.

The combined wealth of the millionaires, defined by Merrill Lynch as "high net-worth individuals", grew by 9.4% to $40.7tr, demonstrating once again the truism that the wealthy get wealthier. The average assets held by high net-worth individuals now exceeds $4m.

The number of super-rich - defined as people with more than $30m - increased by 8.8% to 103,320.

The report also details the different tastes of the wealthy in different parts of the world. In Europe, they spend 22% of their spare cash on art; 17% on "luxury collectibles", including cars, jets and boats; 12% on luxury travel; and 6% on sport, including buying teams and racehorses. In Asia, their most popular items are jewellery, gems and watches, accounting for 19% of their spare money, followed by "luxury consumables" such as designer clothes.

"This year's report found that the number of high net-worth individuals, and the amount of wealth they control, continued to increase in 2007," said Nick Tucker, executive director at Merrill Lynch's global private client group. "We expect the environment to remain challenging over the next six to 12 months but long term the trends remain intact."

In Britain, there are 494,500 dollar millionaires, the number advancing by 2.1% last year, far slower than the European average of 3.7% but still faster than France and Germany. The UK remains home to about 5% of the world's dollar millionaires, ranking it fourth in the world, though that could change if threats to quit Britain made by "non-doms" angered by changes to the tax laws are carried out.

Tucker said much of the high wealth in Britain is now entrepreneurial, in contrast with 10-15 years ago when it was largely inherited. However, he said the number of wealthy individuals in Britain could slip into reverse in 2008 if the economic conditions persist.

The growth in new millionaires in 2007 had slowed significantly from 8.1% in 2006. According to Merrill Lynch forecasts, there will be more millionaires in China than in Britain by the end of next year. Ireland was one of the few countries last year in which the number of dollar millionaires fell - by 4% to 20,000 - reflecting a slide in the Dublin stockmarket, inflationary pressures and a downturn in the property market.

"I'm not predicting that will happen in the UK yet but it is quite possible," Tucker said.

"If the property market and the stockmarket conspired against it then the UK could possibly see the same thing happen." He said that if conditions in the second half mirrored the first then the United States, which has suffered a collapse in its property market, could also see a decline in the number of millionaires this year. The number of millionaires in North America expanded by 4.2% last year, down from 9.2% in 2006.

Tucker said there had been a divergence between developed and emerging markets in the second half of last year. "Mature economies have had significantly slower growth compared with other regions and compared with last year."

The acceleration in emerging markets was supported by strong GDP growth and soaring local stockmarkets. The total market capitalisation of the Bombay exchange expanded by 118% in 2007; China's stockmarket grew by 291% and the Bovespa in São Paulo expanded by 93%, as foreign investors flooded into Brazil. In Britain, by comparison, the market capitalisation of the London stockmarket contracted by 1.5% during 2007.

The number of dollar millionaires in the Middle East grew by 15.6% last year. The high-net-worth population in eastern Europe grew by 14.3%, compared with growth of 3% in western Europe, though the relative numbers still show a wide disparity in wealth. There are 1.8 million in western Europe and only 235,000 in the less mature eastern markets.

Historically, investments in art, private planes, luxury cars and other high-priced collectibles have been more resistant to economic downturns because the super-rich buyers tend to be less impacted by recessions than average earners. The bad news for millionaires is that their dollars are not stretching as far they used to. According to Merrill Lynch, they face personal inflation rates of 6.2%.

Although the global economy is looking fragile in the short term, the report forecasts continued growth in the medium term. It suggests that the global wealth of high net-worth individuals will grow to $59.1tn by 2012, advancing at a rate of 7.7% a year.