Students at New York University, along with the AFL-CIO’s president, John Sweeney, and other labor leaders, plan a rally in Washington Square today to pressure the school’s administration to negotiate a contract with graduate assistants.

Labor leaders and students who support contract negotiations said the demonstration is the next step toward a possible strike by graduate students, which could cause major academic disruptions for the university.

“Anything is on the table for the fall,” a fifth-year Ph.D. student in American studies, Michael Palm, said. He is unit chairman for the Graduate Student Organizing Committee, a bargaining unit within Local 2110 of the United Auto Workers. UAW officials say they represent about 1,000 NYU graduate students.

NYU officials said they have no intention of backing down from their refusal to renegotiate the graduate assistant contract, which expires today. The administration is girding for the possibility of a strike of its teaching and research assistants, an NYU spokesman, John Beckman, said. A strike could lead to course cancellations and disrupt campus research, as happened at Columbia University in the spring of 2004 when graduate students went on strike for the last few weeks of the semester.

Starting tomorrow, NYU will no longer recognize the UAW as an intermediary between the administration and its graduate assistants. For the past three years, NYU was the only private university to have unionized graduate students. The University of Wisconsin, the University of California, and the University of Michigan are among public universities that have unions of graduate students.

Rally organizers said they hope the demonstration, scheduled for between noon and 1 p.m. outside the university’s Bobst Library on Washington Square South, will generate more sympathy for their cause among members of the NYU community, particularly faculty members.

“We want to make it clear to NYU that the wider university community and allies are demanding that the university bargain in good faith,” the president of Local 2110, Maida Rosenstein, said.

Among the labor leaders expected to participate in the rally are Mr. Sweeney; the president of the New York State AFL-CIO, Denis Hughes, and the president of the United Federation of Teachers, Randi Weingarten. A Democratic mayoral candidate, Gifford Miller, the City Council speaker, is also expected to attend, as is the actress Morgan Fairchild, who is a candidate for president of the Screen Actors Guild.

NYU announced its decision not to renegotiate a contract with the union in August, about a year after the National Labor Relations Board ruled that universities no longer were legally obligated to recognize graduate students’ unions. Graduate assistants are primarily students, rather than workers, and thus do not have the right to collective bargaining, the board concluded.

The dissenting members of the board argued that the majority minimized the economic relationship between graduate assistants and their universities.

“It errs in seeing the academic world as somehow removed from the economic realm that labor law addresses – as if there was no room in the ivory tower for a sweatshop,” the dissenting opinion stated.

The board’s three-to-two ruling in 2004, in a case involving Brown University, overturned a 2000 ruling during the Clinton administration that forced NYU to recognize its graduate student union. The 2000 decision was the first time the board ruled in favor of graduate students’ unions, after three rulings against them since 1976.

In announcing its decision, NYU’s administration said it would increase annual base stipends for teaching and research assistants by $1,000 in each of the next three years, to $21,000 from $18,000. In the 2005-06 academic year, graduate assistants will each receive financial-aid packages of at least $50,000, an amount that includes an $18,000 stipend, $30,000 in tuition remission, and $2,000 in health insurance plan premiums, Mr. Beckman, the NYU spokesman, said.

“It is certainly fair to say that NYU stipend levels are competitive with the top universities in the country and are higher than many universities,” Mr. Beckman said. Union leaders said the increases in stipends are the result of union bargaining.

NYU officials have also blamed the UAW for filing what they considered to be bogus grievances, which wasted school resources and threatened the academic prerogative of the university to decide who teaches what courses. The union, for example, filed a grievance to protest the university’s decision to offer certain positions as teaching assistants in NYU’s Morse Academic Plan, a core curriculum for undergraduates, to non-NYU graduate students. An arbitrator ruled against the union.

NYU officials said the grievances filed have caused the administration to lose trust in the union’s promises to abide by a contract, while union leaders have told the university the union would withdraw grievances that the administration found to be objectionable.