The leadership of Roman Catholic women's religious orders in this country will confront representatives of the Vatican here today over what they perceive as efforts by Pope John Paul II to turn back the clock on modernization efforts within their orders.

A record number of nun-administrators will meet in closed-door sessions this morning with Archbishop John R. Quinn of San Francisco and Archbishop Pio Laghi, personal representative of the Vatican in this country. Quinn heads an extraordinary papal study commission named earlier this year to assess the "renewal" of men's and women's religious orders in the United States.

Many of the more than 700 women gathered here for the annual meeting of the Leadership Conference of Women Religious, the umbrella organization representing more than 90 percent of women's religious orders in this country, fear the study may be the first step in forcing nuns back into more traditional roles and life styles.

"We cannot . . . become caterpillars again," declared Sister Juliana Casey of Detroit, in a speech that ostensibly addressed the role of women in working for world peace. But broad sections on conflict and the misuse of power applied equally to the differences between American Catholic sisters and the all-male power structure of their church, Casey said afterward in response to a question.

American nuns have moved faster and further than most segments of the church in the modernization called for by the Second Vatican Council 21 years ago. They abandoned centuries-old habits for contemporary dress, turned over parochial school classrooms to lay people in order to pursue a wide range of ministries and moved out of convents to live among the people of the communities they served.

Influenced both by their reading of Scripture and secular liberation movements, many have pressed for more equitable roles for women in the male-led Catholic Church.

The Vatican-mandated study, which Leadership Conference leaders learned about from the news media, is widely perceived as an attempt to overturn many of the reforms.

In an unusual move, the organization closed its business sessions to the media this year to facilitate "an openness among us . . . without the press," explained the president, Sister Helen Flaherty. "We are very vulnerable because we really don't know what this is going to come to," she said.

In her address on peacemaking, Casey, who was a consultant representing American nuns on the committee of U.S bishops that drafted their landmark statement condemning nuclear warfare, never mentioned the authority crisis facing American nuns.

But from the questions raised by members of the audience after the speech, it was clear they understood that Casey was not discussing geopolitics alone when she spoke of "dominants" and "subordinates" in situations of "long-term inequality . . . ."

"When subordinates seek to move beyond the limits and stereotypes set for them, they invariably cause conflict, or rather, do not so much create conflict as expose the fact that conflict already exists," Casey said.

Pulling together the overt and the covert themes of her address, she told the women: "We cannot go backwards; nuclear weapons are a fact . . . . The Second Vatican Council happened 20 years ago, and we have been transformed by that time of grace . . . . The raising of women's consciousness has raised our own and we cannot deny what we know."

Casey received a standing ovation.