A bipartisan group of former high-level government officials is trying to mobilize grass-roots American support for the World Bank and the International Monetary Fund, whose funding requests have run into increasing problems in the U.S. Congress.

"You are in trouble in a participatory democracy when you don't have a constituency," said Charls E. Walker, a lobbyist for business interests and deputy Treasury secretary in the Nixon administration. Until now, the beleaguered multilateral lending agencies have had no constituency in this country, he noted.

Walker and Henry H. (Joe) Fowler, President Johnson's Treasury secretary, will head the new organization, called the Bretton Woods Committee, which plans its first meeting here on Jan. 22. Other organizers include Henry Owen, who served in the Carter White House on international economic issues, and Edward R. Fried, the U.S. executive director of the World Bank during the Carter administration.

Walker said the committee's major effort will be "to create a climate of understanding" in the country for the World Bank, which supplies loans to Third World countries for development projects, and the IMF, which loans money to industrialized as well as Third World countries to help them pull out of external financial problems.

The committee was started, Fowler said, because of close votes in Congress on recent funding measures for the IMF and World Bank and because of an organized effort by conservative groups against the multinational organizations. The anti-IMF and World Bank forces ran radio ads in 20 states that "didn't tell the full story or the right story," Walker said.

"We want a more balanced debate," added Fowler.

Walker said the organization aims to create a grass-roots climate of support for the IMF and the World Bank so that lawmakers who vote in favor of the world bodies "will not be hanging out all alone" when they go home.

The committee organizers said they will emphasize the importance of those organizations and the health of Third World nations to the economic vitality of the United States in a world that has become increasingly interdependent.

"The Reagan administration has become educated by experience as to the importance and values of those institutions" and now is "fully supportive of them," Fowler said.

IMF Managing Director Jacques de Larosiere, World Bank President A. W. Clausen and Paul A. Volcker, chairman of the Federal Reserve Board, will address the committee's first meeting Jan. 22, to which 130 persons have been invited. The committee expects to spend about $200,000 this year, raised from individuals, corporations and foundations, and is aiming for a membership of about 300.