EUROPE'S largest clothing retailer, Spain's Inditex, is taking its flagship Zara brand online.

Zara's virtual boutique will be available on Thursday in selected European markets: Spain, Germany, France, Italy, Portugal and Britain.

From next year, it will also be available in the United States, Japan and South Korea.

But it will enter an already crowded sector, where its main rivals in low-cost fashion have been operating for years.

US retailer Gap, which has been online in the US since 1997, expanded the service to 55 countries on Aug 16.

Sweden's H&M, Europe's second- largest clothing retailer, has been selling online since 1998 in seven countries, and plans to move into another major market, Britain, on Sept 16.

But clothing sales represented just 2.5 per cent of online commerce in Spain last year, and 5.6 per cent in France, according to industry experts.

Another high-street brand, Mango, has been online since last year, but receives only about 1 per cent of its revenues in this way.

Gap has performed better, pulling in US$1.1 billion (S$1.5 billion) in online sales last year, or 7.7 per cent of its total. Still, a recent poll by the Nielsen Institute in 55 countries showed that clothes are now the second-most-popular products online, after airline tickets.

And in Britain, almost 10 per cent of clothing is purchased online.

Inditex - which owns seven other brands, including Massimo Dutti - said the move online would boost sales rather than eat into the earnings of the shops.