Supporters of the equal Rights Admendment staged a downtown rally today in an attempt to persuade Ronald Reagan to moderate his positions on women's issues that now divide the Republican Party.

ERA supporters, led by Helen Milliken, wife of the Republican governor of Michigan, also have scheduled a march Monday before a meeting with the expected GOP nominee Tuesday.

"Equal rights with a small E an a small R will not do," said Milliken. "The Equal Rights Amendment is a good Republican conservative issue . . . The ERA is the guarantee to a free market economy for women."

But Reagan appeared unmoved by events in Detroit.

In an interview with CBS' "60 Minutes," a special program, to be shown Monday, Reagan said he thought the platform committee had found "some middle ground" on a question that "either way you went, you estranged and angered one group" or another.

"I'm for equal rights," he said. "I can prove it by my record."

Reagan Saturday night agreed to meet Tuesday with ERA supporters, outraged by the party platform committee's rejection of a plank endorsing the amendment. The sessions will include some of the party's highest ranking and most articulate respresentatives, including Sen. Nancy Landon Kassebaum (Kan.), Rep. Margaret Heckler (Mass.), former national GOP co-chairman Mary Louis Smith and seven platform committee members.

"I think the platform committee too [reagan] far beyond what he would have liked," Heckler said. "I hope Gov. Reagan will be more reasonable than the platform committee.

"We hope he will clarify his views on equal rights, especially in terms of recruitment of women in his administration," the congresswoman added.

"This is especially important now when such negative impression was left" on Reagan's approach to the ERA.

Betty Heitman, president of the National Federation of Republican Women and believed to be Reagan's choice as the next co-chairman of the party, has also been invited to the session. But she said today that she did not know if she would attend. "I don't think it's right for Gov. Reagon to sit down with some people who are supporters of John Anderson," the Republican congressman and independent presidential candidate, she said.

But Heitman and other Reagan supporters are beginning to voice misgivings about the platform committee's failure to endorse ratification of the Equal Rights Amendment, which had been in every GOP platform since 1940.

As a concession to pro-ERA forces, the platform committee adopted language calling the actions of supporters of ERA "legitimate."

"There's no question that the smartest thing that the committee could have done would have been to keep the language they had in 1976," Heitman said.

William Casey, Reagan's campaign manager, said the publicity coming from the committee's action in opposing the ERA and supporting a constitutional amendment banning abortions, had not been helpful to the Reagan campaign.

Casey said he thought the negative impact eventually could be overcome. "It'll never go away, but I don't think it will be a major issue," he added.

ERA and abortion pose a dilemma for Reagan. He opposes both. His campaign has been based on an appeal to a "new set of shared values" -- including the family, women staying at home and the work ethic.

But there is a conflict of values in the party, especially among the party activists, both moderate and conservative. Put simply, conservative women now have abortions, just as liberals do. They work in what once were thought to be "men's jobs." They want equal pay for equal work. Even Reagan's daughter, Maureen, 39, supports the amendment and testified in its behalf before the platform committee.

For 40 years, this has been the policy of the Republican Party as well. The shift, former President Ford said today, "will not gain any votes and will probably lose votes" in November.

Appearing on "Issues and Answers" (ABC, WJLA), Ford said he could "basically support" the GOP platform, but he continues to have a "strong commitment to ERA" and thinks abortion questios should be handled through legislation rather than constitutional amendment.

At a rally of several hundred ERA supporters on Cadillac Square today, Gene Brazell, a middle-aged woman who normally votes Republican, expressed the dilemma the party faces on the issue. She works with older women -- especially widows and divorcees -- trying to reenter the work force, at Henry Ford Community College outside Detroit.

"The platform is an insult to me and every woman I work with," she said. "There's no way I could go along with the Republican Party this year with that plank around.

"The trouble is so many women have just bought the Phyllis Schlafly line hook, line and sinker," she added.