George Mason University officials said yesterday they plan to discipline a fraternity and a sorority involved in a fund-raising event in which a white male student was dressed as a black woman.

"This is inappropriate behavior," said Dean Kenneth E. Bumgarner, who will decide on specific sanctions this week. "It's not acceptable and we won't condone it."

The incident occurred at a charity fund-raising event April 4 sponsored by the Sigma Chi fraternity in a student union building on the Fairfax County campus. As part of a "Dress a Sig" competition, women from six sororities dressed 18 Sigma Chi members in female clothing and paraded them across a stage.

One fraternity member, dressed by members of Gamma Phi Beta sorority, wore a blouse, a wig, blackface and a pillow strapped to his posterior under a skirt.

"It did happen. We don't deny it, and for that we apologize," said Sigma Chi President John Singsank, 23, who noted that three of his 57 members are black. "It wasn't meant to stereotype or malign any race or gender. It was just good fun."

The university's response reflects a growing concern over racism on college campuses that in part prompted Gov. L. Douglas Wilder recently to demand Virginia college officials work harder to foster "campuses of civility."

Two years ago, two sororities at Virginia Tech were reprimanded for holding blackface shows based on scenes from "Gone With the Wind."

And last year, the University of Virginia became embroiled in a racially tinged dispute when students elected a black man as student government president.

The George Mason episode also underscores the debate over the propriety of universities punishing student expression considered insensitive, a controversy fueled by Brown University's recent expulsion of a student who allegedly uttered racist and antisemitic comments.

Some students who attended the George Mason fraternity event said the episode has been blown out of proportion.

"I can't believe anybody's getting upset about this," said Wanda Bailey, 21, a junior who attended the fund-raising event. "It was all supposed to be fun."

Some others did not see it that way. A campus forum will be held today to permit upset students to meet with fraternity and sorority leaders, and the Student Coalition Against Apartheid and Racism plans a demonstration at the same time.

"I hope they didn't think it was just fun," said Tamara Green, 21, a junior and sorority leader who was not present at the fund-raiser. "A group was attacked in a way that just reinforces stereotypes . . . . I'm offended as a black female."

University spokeswoman Helen Ackerman said the fraternity and sorority are being punished because the incident was "stupid and destructive to campus civility." Bumgarner said the university's code of conduct requires students to respect the rights and needs of others.

Possible sanctions could include probation, community service, mandatory educational workshops or banishment from campus, according to Bumgarner. Penalties for individual students are not being contemplated at this time, but he did not rule them out. Bumgarner stressed, "This is an opportunity to create an educational setting where they can learn from this."