A high Treasury official yesterday explicitly recognized the greater force in world affairs being played by developing countries, and said that "a number of global problems" of importance to the United States could be resolved only with their help.

C. Fred Bergsten, assistant secretary of Treasury for international affairs, cited as a case in point the need for developing country support on questions relating to the taking of U.S. hostages by Iran, and the Russian invasion of Afghanistan.

In a speech in New York, Bergsten said that the U.S. needed the help of developing nations on key votes in the United Nations, and in other ways to bolster the American response to Iran and the Soviet Union.

"It is a simple truism to recognize that the prospect for less-developing-country (LDC) support on such issues of primary importance to the United States will be enhanced by U.S. co-operation on issues of keen interest to them," he said.

A main theme of Bergsten's address -- to the Center for Inter-American Relations -- is that the confrontation between the industrialized "North" and the developing "South" that existed in the 1970s has been replaced by a quieter dialogue that has benefitted both groups.

He admitted that rhetoric had been strong on both sides; and that the United States had even refused to talk about a number of issues given high priority by the poor nations, including the much-debated "common fund" to support commodity prices.

He recalled that during the era of President Ford's Treasury Secretary, William E. Simon, the U.S. had put a flat ceiling on the lending program of the World Bank, and allowed subsidized aid totals to fall to the lowest point (relative to GBP) since World War II.

That policy posture has shifted dramatically, Bergsten said, with U.S. support of a $40 billion capital increase for the World Bank, and progress on a number of other fronts.

Overall, 500,000 U.S. jobs depend on total exports to this group of nations. In turn, the U.S. is highly dependent on them for a number of critical raw materials and agricultural products.