The chairman of the International Trade Commission warned yesterday that America's growing merchandise trade deficits are unlikely to be turned around by a lowering of interest rates and a decrease in the value of the dollar.

Citing a study released yesterday by the ITC, Chairman Alfred E. Eckes said other factors are often equally as important as the high value of the dollar in hurting U.S. sales overseas and encouraging the heavy flow of foreign goods here.

"We should not conclude that when the dollar falls, our trade deficit will vanish. In fact, there is now reason to question the conventional wisdom that exchange rates alone dictate trade flows," Eckes told the National Press Club.

"A decline in the dollar will undoubtedly provide some relief to beleaguered American industry," he continued, "but a falling dollar will not end the import challenge."

The dollar's soar since 1981 in relation to other world currencies has been blamed for a large part of America's trade deficit, especially with Japan, by making foreign goods less expensive here and raising the cost of U.S. products overseas.

"Exchange-rate movement cannot always be assumed to be the predominant factor which determines changes in trade flows with respect to any individual product," the ITC study found.

That "generalization," it said, "overstates their importance" compared with other factors, especially changes in competitors' prices, demand for the product, local production and manufacturing costs, which play key roles in changing world trade flows, the ITC reported.

For instance, the study found that U.S.-French trade balances improved slightly even though the dollar grew in value 21 percent against the franc between 1981 and 1982. In Germany, on the other hand, the U.S.-West German trade deficit worsened considerably while the dollar increased in value by 7 percent against the deutschemark.

The range of factors influencing trade flows varied from country to country, even with the same product. The strength of the dollar, for instance, was found to have played a minor role in influencing trade in magnesium between the U.S. and Japan. The dollar's value, however, was significant in hurting U.S. sales of magnesium to the European Community, where U.S. exports faced stiff competition from Norway, also a low-cost producer and the second-largest exporter after the United States.

Eckes called "the growing challenge of imports to domestic industry . . . as important to this decade as energy was to the 1970s."

Eckes predicted that other industries are destined to face the same problems from imports now hurting the U.S. shoe, clothing, steel and auto industries.