Yale University has taken "significant" disciplinary action against a senior faculty member accused of sexual misconduct, a school official said yesterday.

Yale Deputy Provost Charles H. Long refused last night to comment on the details of the punishment, but said the professor's actions were found to be in violation of university policies.

The Yale Daily News reported last month that Stephen Kellert, a Yale School of Forestry professor, admitted to making sexual advances four years ago toward Katheryn Joost, then a prospective graduate student.

Neither Long, who began investigating the case this fall after Joost filed a written complaint with the university secretary, nor the dean of the School of Forestry, Jared Cohon, has labelled Kellert's behavior sexual harassment.

According to the Daily News, Cohon determined Keller's punishment after reviewing facts presented by Long. Cohon's reprimand will remain on Kellert's permanent employment record, the paper reported.

In an interview from her home in Eugene, Ore., last night, Joost, 35, said it was her understanding that the Yale administration does not plan to inform her of Kellert's specific punishment.

Joost, now a graduate student at the University of Oregon, said she did not know why the Yale administration did not classify Kellert's behavior as sexual harassment. She said she made it clear in her complaints that she believed Kellert sexually harassed her.

But she said she is pleased that Yale has officially announced that Keller's actions violated university conduct rules.

Kellert did not deny making advances in June 1988 toward Joost, but told the Daily News that he retreated after her initial hesitation.

Joost first met Kellert at a 1987 conference in Montana. The two discussed the possibility of her coming to Yale to study at the School of Forestry, and then months later spoke on the phone to arrange her visit, according to the Daily News.

The four-year lag between the incident and a formal complaint was due partly to Joost's misunderstanding of Yale's sexual harassment policy.

Long said as a result of this incident, Yale will now make a small but significant change in the way it publicizes disciplinary policies in order to clarify a visitor's option of bringing forward complaints. The school's sexual harassment policy includes prospective applicants such as Joost, he said.

According to Long Joost first approached Yale's Affirmative Action Office and the dean of the faculty of arts and sciences four years ago about the incident, but was not instructed on how to proceed with her allegation.