ALBANY – The state lobbying commission is looking into the possibility that U.S. Senate candidate Jeanine Pirro reimbursed a pharmaceuticals company retroactively for a ticket to a social event during last year’s Republican National Convention, only after learning that the admission fee might qualify as an illegal gift under the state’s lobbying statute.

The lobbying commission does not confirm or deny its investigations, which focus on lobbying groups rather than politicians. But commission officials released materials yesterday, connected to a Manhattan social event in honor of the wife of Governor Pataki, that raise questions about the legality of payments by two people who attended the event, including Mrs. Pirro.

State lobbying law forbids the acceptance from lobbyists of gifts valued at more than $75, unless recipients pay for them in advance or agree in advance to pay for them later. Mr. Pataki’s wife, Libby, paid for the Aug. 30 tea ahead of time, out of her husband’s campaign fund. Mrs. Pirro paid for the event, which was valued by organizers at $350, nearly two months later.

At issue is whether Mrs. Pirro, who is regarded by many as the Republican front-runner to challenge Mrs. Clinton’s re-election bid next year, paid for the event after learning that its sponsor, the pharmaceuticals maker Astra Zeneca, was being investigated by the lobbying commission. Because the ticket was repaid, it may not qualify as a gift. If Mrs. Pirro accepted without intending to repay, however, the acceptance could qualify as a misdemeanor.

“If there isn’t agreement to pay, it’s a violation of the Lobbying Act and a misdemeanor,” the lobbying commissioner, David Grandeau, said.

According to a letter sent to the lobbying commission by lawyers for the Friends of Pataki campaign committee, seven individuals covered by the Lobbying Act paid for the event in advance: Mrs. Pataki; her daughter Emily; the lieutenant governor, Mary Donohue; the state’s health commissioner, Antonia Novello; Mr. Pataki’s mother, Margaret; the state’s banking superintendent, Diana Taylor, and an employee of the state university, Karen King.

Two individuals covered by the act paid after the Manhattan event: the sister, Mary Cahill, of the governor’s secretary, John Cahill, who sent a check in November, and Mrs. Pirro, whose Friends of Jeanine Pirro campaign committee sent a check October 26.

A spokesman for Mrs. Pirro did not return a call seeking comment on the circumstances surrounding the payment.

Mrs. Pirro, who is district attorney of Westchester, announced earlier this month that she will seek the Republican nomination to challenge Mrs. Clinton. Other Republicans looking to challenge the former first lady include a Manhattan lawyer, Edward Cox, who is married to President Nixon’s daughter, Tricia, and a former mayor of Yonkers, John Spencer.