"This is a strategic move that will open up luxury to the entire nation," said Federico Marchetti, founder and chief executive of Milan-based YOOX SpA, which created the site for the Giorgio Armani SpA label. Mr. Marchetti said at a news conference that YOOX plans in the next year to open Chinese sites for three or four clients he didn't name. Dolce & Gabbana Srl, Ermenegildo Zegna Holditalia Spa and Valentino SpA are among the e-commerce company's 23 clients.

Other companies—including PPR SA's Gucci, Burberry Group PLC and Italian shoemaker Tod's SpA—say they also have plans to cash in on China's exploding population of online shoppers.

The decision by high-end brands to sell their handbags and clothing directly to Chinese shoppers via the Internet marks an attempt to push deeper into a nation with consumers eager to mark their new wealth by buying flashy labels.

Luxury goods have been available for several years on the Chinese Web. But that generally has been through middlemen who offer an array of brands, many of them out-of-season, rather than directly from the labels. Western sites are available to Chinese shoppers only to a limited degree, in part because not all company sites offer shipping to China. Also, steep Chinese import duties discourage buying from vendors' overseas sites.