The U.S. delegation to the U.N. Decade for Women Conference has surprised observers here this week by agreeing to feminist demands that go far beyond existing laws and customs in many of the participating nations, including the United States.

In committee meetings, the U.S. delegation has agreed to support language calling for "equal pay for work of equal value," for "legislative measures" that would eliminate "wage differentials between men and women carrying out work of equal value," for government funding of women's organizations and for "accessible child care facilities for working parents." There has also been agreement on a measure calling on governments to include the "unremunerated contributions of women" -- such as house cleaning, child-bearing and cooking -- in calculating the gross national product.

But implementation of these resolutions, to be compiled next week in the final report of the conference, appears unlikely in many of the 159 countries in attendance. Thus the willingness of countries such as the United States to support resolutions opposed by their governments back home raises questions about the practical impact of the conference.

In the case of the United States, the contradictions have angered American feminists who have traveled here to observe the conference proceedings.

The U.S. delegation -- which is headed by the president's daughter, Maureen Reagan, and which insists that it speaks for the U.S. government -- has agreed during the past week to support measures such as the call for "equal pay for work of equal value" that appear to run counter to Reagan administration policy.

When asked about those agreements, Ambassador Alan Lee Keys, the only male on the U.S. delegation, who has emerged as the key voice on policy, said that "in the interest of compromise and consensus we were willing to go along" during committee meetings on resolutions.

He added, however, that the United States reserves the right at any time to withdraw its agreement and attach dissenting notes to the conference's final document.

"It won't imply any changes in U.S. policy at all, if it comes to that," Keys said.

The conference's final report does not have any legally binding force upon the governments that sign it, a U.N. official said. "But women's groups and nongovernmental organizations can use it to pressure governments. They can say, 'If you didn't agree to it, why did you sign it?' "

Maureen O'Neil, deputy head of the Canadian delegation, which has taken a leading role in the conference, said that by agreeing to the language of the conference's resolutions nations "undertake a moral commitment. It is not like ratifying a legal convention. Nothing takes effect immediately. It has progressive implications. It says a nation's policies must move in a certain direction."

But American feminists here are questioning the sincerity of the U.S. commitment. "The U.S. delegation is coming into this conference supporting domestic policies that back in the United States they aggressively oppose," said Kathy Bonk of the National Organization for Women.

One senior member of the U.S. delegation, White House assistant Linda Chavez, has made frequent speeches against the concept of "equal pay for work of equal value," or "comparable worth," according to Bonk. The Reagan administration's Justice Department also has opposed the concept in briefs filed in a Washington State case.

The Reagan administration also discontinued funding for the President's Advisory Commission for Women in 1981, the first administration in 20 years to let the commission's charter lapse. This runs counter to language approved here supporting government funding for women's organizations.

Another conference goal agreed to by the U.S. delegation affirms the need to support teaching methods that "clearly demonstrate the equality of the sexes." Since 1980 the Reagan administration has asked for no funding for the only federal program related to nonsexist teaching methods, the Women's Educational Equity Act. The $6 million program has been approved each year by Congress.

There is widespread support by women delegates from around the world for the symbolic, if nothing else, importance of the final report that is emerging from the conference. While women from Syria, Nicaragua, the Soviet Union, Cuba, the Palestine Liberation Organization and South Africa's African National Congress all attacked the United States in speeches, they also called for greater rights for women.

"Yes, nothing has changed on the political aspect," said Nitza Shapiro-Libai, a member of the Israeli delegation. "But on the women's issues, one can certainly notice that in the past 10 years the consciousness of the world has been raised. There is a unanimous demand for equality."