China is poised to dominate the more than $400 billion global market in clothing, and India will also significantly increase its clothing exports starting in 2005, when import restrictions are eliminated in the United States and other rich nations, according to a World Trade Organization study released yesterday.

But the report said that while many developing countries will suffer significant losses amid stiff new competition from China and India, a number of nations such as Mexico and Turkey should be able to maintain their positions as major clothing exporters because they are geographically close to the big markets of the United States and the European Union.

The WTO report is the latest in a series of warnings that tumultuous transformation is set to begin next year in the world textile and apparel industry, a crucially important sector because it is historically the first rung on the ladder of industrialization for developing countries.

The system that has governed most international trade in the sector for more than three decades is set to expire on Jan. 1 under a WTO agreement struck in 1995. The old system has allowed rich nations -- chiefly the United States, Canada and the E.U. -- to set quotas, or ceilings, on the amount of textiles and apparel that they import from individual countries. That has allowed them to protect their domestic firms and workers from low-wage competition to some extent, although the rising tide of cheap clothing already has destroyed much of the U.S. industry.

Once the quotas are eliminated, the lowest-cost and most efficient producers will be free to export as much as they want, and many experts have predicted that China will emerge as the biggest winner by far.

Some U.S. executives have publicly forecast that China could grab up to 80 percent of the U.S. clothing market. Earlier this year, the U.S. International Trade Commission, an independent agency, released a report based in large part on interviews with industry sources around the world. That report said China is "expected to become the 'supplier of choice' for most U.S. importers . . . because of its ability to make almost any type of textile and apparel product at any quality level at a competitive price."

That prospect has fueled mounting protest from U.S. textile and apparel firms, as well as from companies in some developing countries that once favored scrapping the quotas but are now having second thoughts. The U.S. industry has mobilized an effort to extend the quotas until 2008, and in recent weeks Mauritius, Nepal and Bangladesh have urged the WTO to hold an emergency meeting to consider an extension. The move was strongly opposed, however, by China, India and Pakistan, among others, and doesn't appear likely to succeed.

The issue has become a source of some discomfort for the Bush administration because of the textile industry's political clout in southeastern states, including North Carolina, the home state of Sen. John Edwards, the Democratic vice presidential candidate.

Richard Mills, the spokesman for U.S. Trade Representative Robert B. Zoellick, reiterated the administration's position yesterday that the United States isn't backing the effort to extend the quota system. "The United States will abide by its international obligations negotiated more than a decade ago," Mills said.

Mills emphasized that the administration has come to the U.S. industry's aid. In particular, it has taken advantage of a special provision in the agreement admitting China to the WTO that allows Washington to cap Chinese textile and apparel imports until 2008 in sectors where those imports are surging. That provision is expected to keep Beijing from wiping out its competitors over the next several years, and it was invoked late last year to limit Chinese shipments of brassieres, dressing gowns and knit fabric to the United States.

Using calculations based mainly on cost and efficiency, yesterday's WTO staff report forecast that China's and India's exports will increase dramatically after 2005. In the U.S. clothing market, China's share could shoot up to 50 percent from 16 percent in 2002, and India's share will surge to 15 percent from 4 percent. Mexico's share, meanwhile, would drop to 3 percent, from 12 percent.

In the E.U. clothing market, China's share will rise to 29 percent from 20 percent, and India's will rise to 9 percent from 5 percent, while Turkey's will fall to 6 percent from 10 percent.

But the model used to make those projections doesn't take into account the advantages enjoyed by producers with geographical proximity to the markets they serve, the report said.

"Time to market is important and increasingly so, particularly in the fashion clothing sector," the report said. "Therefore, countries close to the major markets are likely to be less affected by competition from India and China than has been anticipated in previous studies."

Those suppliers include Mexico and the nations of the Caribbean, Eastern Europe and North Africa, which are "likely to remain important exporters to the U.S. and E.U. respectively, and possibly maintain their market shares," the report said. "This is even more likely given the preferential access they have to the markets through regional trade agreements," such as NAFTA.

The countries that are most likely to lose "are those located far from the major markets," the report said. Other losers will include the high-cost local producers in the United States, E.U. and Canada.