American and international public health experts yesterday attacked the Reagan administration's efforts to promote increased exports of American tobacco products to developing countries, predicting that intensive, Western-style marketing of cigarettes will lead to higher death rates worldwide from smoking-related diseases.

"The image that is emerging in Asia is that of a country interested in the sale and promotion not of a healthy product, but of a lethal product," said Dr. Judith Mackay of the Hong Kong Council on Smoking and Health.

Pressure from the White House had forced a last-minute change in the official topic of the meeting of the Interagency Committee on Smoking and Health from trade to the international health effects of smoking, but speakers nonetheless used the platform to criticize U.S. trade policy on tobacco.

Cigarette smoking is increasing faster than the population in developing countries, and Mackay and other speakers said a major reason is the aggressive advertising that has accompanied the entry of American and British cigarettes into countries that formerly had state-run tobacco monopolies, which did not extensively promote their products.

"When the multinationals penetrate, they not only sell U.S. cigarettes but they transform the entire market," said Gregory N. Connolly, speaking on behalf of the American Public Health Association. Connolly said American and British companies introduce brands and advertising designed to appeal to women and teen-agers, which are the groups with the lowest smoking rates.

Smoking-related illnesses cause an estimated 2.5 million deaths worldwide every year, and experts predict that number will rise because of sharply increasing smoking rates in Africa, Asia and Latin America. Connolly noted that smoking has increased 73 percent worldwide since 1968.

Speakers described recent incidents in which American tobacco companies, with assistance from U.S. embassies, trade representatives and some members of Congress, pressured the governments of Hong Kong, Taiwan and South Korea to lift or modify local bans on television or print advertising of cigarettes.

Noting that exported American cigarettes contain no health-risk warning labels, Connolly said, "At a minimum, I think, we should require the same warning labels on packages sold abroad and restrictions on advertising as are required here."

Several speakers condemned policies on tobacco as inconsistent or hypocritical. "We seem to have a tremendous divergence of trade policies from health policies," said Rep. Chester G. Atkins (D-Mass.). "We are sending a message to the rest of the world that we don't really care about anybody else's health other than our own."

Atkins said he will introduce legislation within the next few weeks to require warning labels on exported cigarettes and to prevent the use of U.S. resources or trade sanctions to pressure countries to liberalize their laws on tobacco advertising.

Surgeon General C. Everett Koop, the chairman of the meeting, noted in his opening statement that "international trade is simply beyond the bounds of this committee," but added that the meeting might provide information on health implications to those formulating tobacco trade policies.

He said later that he was pessimistic that such considerations would influence policies. "I'm not hopeful," he said. "It's all I can do."