The union representing New York University graduate teaching assistants is encouraging its members to stage a strike that could extend beyond the fall semester, and lead to cancelled undergraduate courses and exams. NYU officials said there would be stiff consequences for students who go on strike, but they have not detailed any punitive actions.

Graduate assistants at NYU are voting this week on whether to authorize its union, Local 2110 of the United Auto Workers, to call a strike to protest NYU’s decision not to negotiate another contract. NYU stopped recognizing the union’s representative role after its contract with graduate assistants expired at the end of August and it received a green light from the National Labor Relations Board to do so. For a period of more than three years, NYU was the only private university in America with unionized graduate students.

Union officials said they would call for a strike if they receive support from two thirds or more of voters. To be eligible to vote, graduate students must already be members of the union or sign membership cards before submitting their ballots at membership meetings on campus or to a ballot box in the Bobst library. Students who were former or might become graduate assistants can also sign up as members. “The strike is going to be disruptive,” the president of Local 2110, Maida Rosenstein, said.

“We hope and believe that most undergraduates will understand that in the long run, a unionized workforce of teachers will be able to do a better job than a group of workers whose rights have been ignored.”

The union has published a talking points memo on its Web site to help graduate assistants justify a strike to undergraduates. NYU this semester has about 1,000 graduate assistants who grade papers and exams, teach, and hold office hours, among other activities. They frequently teach sections of the Morse Academic Plan of the College of Arts and Science, which is a set of core curriculum requirements, and foreign language courses.

NYU’s graduate assistants are among the best paid top-tier universities. In the 2005-06 academic year, the minimum annual stipend for doctoral students is $19,000. That will rise to $21,000 by fall 2007.

NYU covers the tuition of its graduate assistants and pays 100% of student health insurance premiums. In a letter to undergraduate students sent out Thursday, NYU’s president, John Sexton, said the union is “embarking on a regrettable and unfortunate course.”