A judge on New York State’s highest court is unvaccinated and could be removed from the bench.

A judge on New York State’s highest court could face removal from the bench for failing to comply with the state’s Covid vaccination mandate, according to court guidelines and state officials.

Jenny Rivera, an associate judge on the state Court of Appeals, has participated remotely in the court’s activities since the fall, when the state court system’s vaccination mandate took effect and unvaccinated employees were barred from court facilities.

She is now one of four state judges who face referral to the state’s Commission on Judicial Conduct, according to a person familiar with the process who spoke on background to discuss a personnel matter. The commission could move to admonish Judge Rivera, or remove her from the bench.

Judge Rivera, 61, was nominated to the Court of Appeals in 2013 by former Gov. Andrew M. Cuomo and confirmed by the State Senate to a 14-year term. She had previously served as a tenured professor at the City University of New York School of Law, where she directed the school’s center on Latino and Latina rights and equality.

The seven-member Court of Appeals sits about once a month in Albany. The remaining six judges, including Chief Judge Janet DiFiore, have met in person since October, while Judge Rivera has appeared by video conference.

Judge Rivera’s chambers could not be reached for comment Tuesday. A spokesman for the Court of Appeals declined to comment.

Since September, court employees have had the chance to either get vaccinated or apply for a religious or medical exemption. Monday marked the end of the review process for those applications. Lucian Chalfen, a spokesman for New York’s Unified Court System, said that about 1,300 people had requested religious or medical exemptions and about half were granted.

On Monday, Mr. Chalfen said, court administrators told 156 court employees — along with the four judges — that they failed to meet qualifications for employment, and if they do not comply with the vaccination requirements in the next two weeks they would be fired. The judges face a different process — the commission, which investigates complaints of judicial misconduct, would hold confidential hearings, but its findings would ultimately be public.

Mr. Chalfen said one of the four judges is based in New York City — Judge Rivera keeps chambers in New York City — and three are elsewhere in the state.

Jonah E. Bromwich contributed reporting.