WASHINGTON, March 5— A Federal district judge considered today the legality of Hillary Rodham Clinton's influential role in formulating health policy for the nation.
At times it seemed that old laws had not caught up with the new realities of the wife of the President serving as his top official adviser on the future of health care in America.
In a lawsuit filed last month, two groups of doctors and health policy advocates invoked a 1972 law, the Federal Advisory Committee Act, to insist that meetings of the President's Task Force on National Health Care Reform be "open to the public."
The law generally requires Federal advisory committees to conduct their business in open meetings. But it makes an exception for "any committee which is composed wholly of full-time officers or employees of the Federal Government." The plaintiffs contend that Mrs. Clinton's group does not qualify for an exemption because she holds no job in the Government. 300 on Health Staff
Mrs. Clinton is chairwoman of the health panel and orchestrates the work of its staff of 300 to 400 people, who are trying to prepare a legislative proposal to submit to Congress by May 1.
At a hearing today before Judge Royce C. Lamberth of the District of Columbia, lawyers for Mrs. Clinton defended her right to develop health policy for the President in secret.
"Congress recognized historical reality," said Jeffrey S. Gutman, a Justice Department lawyer representing Mrs. Clinton. "The First Lady and the Second Lady assist the President and the Vice President in their duties. The assistance serves the public so much that public funds are warranted to assist them in their enterprise. The First Lady and the Second Lady are Government insiders, members of the Government who perform true public services in the operation of our Government."
"For the purpose of the Federal Advisory Committee Act," he added, "the First Lady is really the functional equivalent of a Government employee."
The plaintiffs acknowledged that an advisory panel composed entirely of full-time Federal employees would not be covered by the open-meeting law. But they said the First Lady could not possibly be a full-time Government employee, or else she would violate an anti-nepotism law that prohibits Federal officials from appointing close relatives to jobs under their supervision. Committee's Power Stressed
Kent Masterson Brown, a lawyer for the plaintiffs, said, "The task force has been wrapped in secrecy from its beginning," and asserted that Mrs. Clinton "doesn't meet the definition" of a full-time Government employee.
"We're not talking about a First Lady placing flowers along the highway," he continued. "We're talking about a First Lady running a committee, a task force that has enormous power, that could enormously affect how we live. The work of this committee could revolutionize the way we see a doctor and could change the tax structure of the country."
Judge Lamberth, who was appointed to the Federal bench by President Ronald Reagan in 1987, said he would rule as soon as possible, perhaps next week. His questions to lawyers did not give a clear signal of how he would rule. Reason for Secrecy Cited
The judge's questions suggested that he, like the plaintiffs, saw the task force as an advisory panel covered by the 1972 law. But he also seemed sympathetic to the Administration's contention that it would be unconstitutional to enforce the law in this case because it would hamper the President's ability to get advice needed to draft health-care proposals for Congress.
George Stephanopoulos, the White House communications director, said the most notable feature of Mrs. Clinton's task force was not its secrecy but its effort to get information from a wide range of outside groups. It is highly unusual for the White House to consult such a wide range of outsiders before the President proposes legislation, he said.
Mr. Stephanopoulos said the White House was withholding the names of 300 to 400 experts working for the task force because if their names were disclosed, "they would become subject to lobbying, to enormous pressure, and would not be able to do the work they have to do in a short period of time."
Conservatives relished the possibility that Mrs. Clinton, a longtime supporter of liberal causes and "public interest law," might be hoist with her own petard. 'Inconvenient' Statutes
"The regime of openness in government has been built by a lot of people sympathetic to Hillary Clinton," said one plaintiff, Peter T. Flaherty, who is president of the National Legal and Policy Center. "Now she would just sweep away those statutes because they're inconvenient to her."
The lawsuit was filed by the Association of American Physicians and Surgeons, the American Council for Health Care Reform and the National Legal and Policy Center.
The association, based in Tucson, Ariz., was founded in 1943 to preserve the private practice of medicine. Dr. Jane M. Orient, the executive director, said the group's 3,000 members support "free-market principles" and oppose government intrusions into the private practice of medicine.
The council said it represents consumers. The center, founded last year, said it seeks to promote ethics in government. Mr. Flaherty is also chairman of the Conservative Campaign Fund, a political action committee.
Mr. Clinton has said he will control health costs and guarantee coverage for all Americans through a mix of free-market forces and government regulation known as managed competition. Under this strategy, employers and individual consumers would band together in big groups to shop for health insurance.