TOKYO, NOV. 12 -- U.S. tobacco companies, dismayed by a shrinking market at home, are rapidly recruiting new smokers in Asia and the developing world, often with the aid of the U.S. government, delegates to an antismoking conference here said today.

The percentage of people who smoke in the industrialized world has decreased steadily in recent years, health experts here said, but the proportion of smokers in developing countries is rising. Tobacco companies have particularly targeted young people and women, who traditionally have not smoked in many Asian countries, they said.

"The industry plan is to create demand among Oriental females," said Gregory N. Connolly, an adviser to the World Health Organization. "If you have one billion Oriental females who don't smoke as a market, that would more than replace the quitters in western Europe and North America. ... And death and disease will follow."

Only 14 percent of Japanese women smoke. But more young women are smoking since U.S. pressure forced Japan to import U.S. brands, triggering a television advertising war between U.S. and Japanese manufacturers, according to Tadao Shimao, former director of the Japan Anti-Tuberculosis Foundation and an organizer of the conference.

After the conference, Donald Harris, a spokesman for Philip Morris International, denied that his company has targeted nonsmokers in the Third World. "We're trying to increase our business every place, whether it's Washington, D.C., or Tokyo or any place we do business," Donald Harris said.

Asked about the health consequences of increasing sales, Harris said, "That's not at issue. The science, we've been through that before, and we're comfortable about that. ... It's a statistical matter, not a direct causal connection."

But Roberto Masironi of the World Health Organization said the rise in smoking in the developing world will lead to "a real epidemic of lung cancer." Worldwide, 600,000 new cases of lung cancer are reported each year, he said; by the year 2000, the number will rise to two million, nearly half of them in China.

Several delegates said that U.S. officials, in their zeal to open Asian markets to U.S. tobacco firms, also have interfered with local government efforts to implement health measures. Among the cases they cited:

Last year, Hong Kong announced that it would become the first Asian country to ban "smokeless tobacco," meaning snuff and chewing tobacco. Elaine L. Chung, deputy secretary for health and welfare, said that the U.S. Tobacco Co., maker of Skol and other chewing tobaccos, lobbied hard against the ban and that a trade official of the U.S. consulate called her to complain.

"My reply was that it was a health issue, not a trade issue," Chung recalled today. "We are very proud of having lowered our infant mortality rate, and we would not want all that effort to bring up our precious children wasted when they become teen-agers, to die some horrible death from oral cancer."

In Taiwan, when the U.S. government pressured Taipei to allow imports of U.S. cigarettes, officials also wanted Taiwan to end its ban on cigarette advertising, arguing that new entries in the market need to advertise. David D. Yen, businessman and chairman of a health foundation, said Taiwan held firm on television advertising but agreed to allow magazine ads.

"Now you go to our dance halls, you can see young girls smoking cigarettes," Yen said.

In South Korea and Japan, U.S. officials lobbied hard for lower duties and taxes on imported cigarettes. When the Japanese health ministry formed a committee to study possible measures to reduce smoking here, the U.S. embassy said in a message to the State Department that the committee "poses the danger that, intentionally or not, action which might discriminate against foreign cigarettes might be recommended and subsequently adopted. The embassy will monitor ... "

"The one thing I've come away with is how much our State Department is an agent for spreading disease," Michael Pertschuk, former chairman of the Federal Trade Commission, said here today. "They're an adjunct of the tobacco industry."

Industry officials said they are seeking to persuade smokers to switch to their brand, not to entice new smokers.

But delegates from dozens of nations said that new smokers, particularly young girls, are being lured by western advertising.

They also said that lung cancer, heart disease and other smoking-related "advanced" illnesses are rapidly catching up to the more traditional causes of death in Third World nations such as infectious disease.

Halfdan Mahler, director general of the World Health Organization, said that tobacco consumption is declining in industrialized nations by 1.1 percent each year and increasing in developing nations by 2.1 percent. "The tobacco promoters seem determined to turn developing countries into their biggest market," he said.

Mahler spoke on the first day of the four-day conference, which was sponsored by the American Cancer Society, the Japan Cancer Society and several other health organizations.