In China's headlong rush to modernize, few things have been so neglected as its past.

Compared with, say, neighbors like Japan and South Korea, this much larger country has rarely done a good job preserving ancient architecture. And despite the incomparable riches of Chinese civilization, world-class museums are few and far between.

For decades, collectors seeking a precious piece of China's past have found overseas markets to be the best bet ¡ª like the auctions and antiques fairs of Asia Week, an annual event that has attracted droves of collectors to New York in recent days. For indignant Chinese officials and archaeologists, such sales are a testament to smugglers' skill in funneling antiquities out of the country and into markets where they will fetch top dollar.

According to some estimates, some 300,000 to 400,000 tombs have been raided in China in the last quarter-century of accelerating capitalist-style development. Although the numbers of looted items are much fuzzier, experts say, the most valuable ones have made their way to the West, with the bulk going to the United States.

For years, China has asked the United States to join its campaign against antiquities smuggling, most recently pressing Washington to adopt a ban on imports of any art or artifact predating 1911, the end of the Qing dynasty. Progress on the issue has been slow, however, partly because of fierce objections from art dealers and collectors.

Nicole Deaner, a spokeswoman for the State Department's Bureau of Educational and Cultural Affairs, said yesterday that China's request was still under consideration and that there was no timetable for when a decision would be made.

Recently there has been a bit of movement on other fronts. In January, China and Italy signed a treaty providing for a new task force of Chinese special agents who will travel to Italy to receive training from the Italian military police in identifying and tracking cultural artifacts.

The two countries also plan a rapid exchange of information about suspected smuggled goods. Chinese experts differ widely on the long-term prospects for controlling the trade in contraband antiques. Yet they agree that the looting of important archaeological sites has slowed somewhat over the last decade.

"It's impossible to absolutely stop this sort of thing, but the mid-1990's was the crazy peak for this market," said He Shuzhong, an official of the State Cultural Heritage Administration, which has been involved in the talks with the United States on tightening import restrictions. "If you look now at the tomb-raiding problem, and you look at the new pieces on the overseas market, things are better than they were 10 years ago. Tomb raiding, although it still exists, and exists seriously in some areas, has decreased by at least half."

Mr. He cited steps taken recently by China to rein in the trade, like new requirements that auction houses and antiques dealers reapply annually for the extension of their licenses. Motion-sensing and satellite-based technology are now used to monitor the best-known sites, and volunteers have been recruited to police them, particularly in the hinterlands.

Still, he said, the most effective remedy would be an American import ban on antiques, adding that he was "annoyed and unsatisfied by America's reaction."

People who do not work for the government agree that the market for illicit antiquities has dried up somewhat. "Smuggling was at its peak between the 1980's and mid-1990's, but now it's relatively subdued," said Ma Weidu, owner and founder of Guanfu, China's first private museum of classic and antique art, in Beijing. "If you went to Hollywood Road in Hong Kong back then, you could see lots of antiquities displayed right there on the street, and they were genuine. Go there today, and you find lots of copies."

As recently as a few years ago, he said, "no one really cared" when excavation work for a big construction project uncovered antiquities, "given the heavy emphasis on economic development."

"Today, when a construction crew hits an ancient site," Mr. Ma said, "the project will be paused, or forced to take a detour."

Still, Mr. Ma estimated that 20 percent of the items he viewed in overseas auctions of Chinese rarities left the country under illegal circumstances.

Lu Jianrong, a professor in the department of heritage, culture and museum science at Fudan University, in Shanghai, said there was little ground for optimism, although he supports the treaty with Italy, which he sees as largely symbolic.

"There is obviously a deep socioeconomic background to this, because our country is in a transition period, and from the perspective of city, county or provincial leaders, the focus should be on people's living standards," he said.

"Antiquities are just not part of the focus," he added, "especially in central and western China, where the living standards are just too low, and where for some, the easiest way to make a living is still to dig stuff up."