ALBANY – Want to know Senate candidate Jeanine Pirro’s position on casino gambling or importing prescription drugs from Canada? You might find yourself talking to one of her two top campaign aides, Kieran Mahoney or Michael McKeon, who are employees of a firm, Mercury Public Affairs, that is registered with the state of New York as a lobbyist for the Shinnecock Nation Gaming Authority and the drug company Pfizer.

Are you a donor to Senator Clinton who wants to know what her position is on merit pay for teachers or American aid to Turkey? You could ask the Clinton campaign’s chief fund-raiser, Patti Solis Doyle, who until recently worked at the Glover Park Group. Or you might be referred to Howard Wolfson, a partner in Glover Park Group – which, according to government filings and press reports, has the United Federation of Teachers and the government of Turkey among its clients.

And those are just some of the disclosed clients of Mercury Public Affairs and the Glover Park Group. Other clients, who aren’t foreign governments or who haven’t engaged the firm to lobby elected officials, don’t have to be disclosed at all.

Some advocacy groups and other Senate candidates say the blurring of the lines between political operatives and lobbyists-for-hire yields conflicts of interest.

Republican opponents of Mrs. Pirro in the campaign for the Republican nomination to challenge Mrs. Clinton are already sending signals they will make an issue of the lobbying work of Mrs. Pirro’s advisers as the race heats up. A spokesman for Senate candidate Edward Cox, Thomas Basile, said Mrs. Clinton and Mrs. Pirro should disclose the clients of the firms advising them.

“There really should be full public disclosure of all the clients,” Mr. Basile told The New York Sun. “For the sake of the public that’s important.”

Mr. Basile said Mr. Cox, a partner in the Manhattan law firm Patterson, Belknap, Webb & Tyler, will disclose his clients at some point in the course of the campaign.

Another Republican in the race, John Spencer, a former mayor of Yonkers, called on the advisers to Mrs. Clinton and Mrs. Pirro to disclose client lists and account for the independence of their positions.

“There’s a crossing of the line here that in my opinion shouldn’t be crossed,” Mr. Spencer said. “These political consulting groups that have gone outside of what their original strength was, which was political campaigns – once they reach out of that area they are setting up potential conflicts, and I think they should be looked at.”

Neither Mercury Public Affairs, which is advising Mrs. Pirro, nor the Glover Park Group, which advises Mrs. Clinton, would release client lists or discuss the potential conflict of interest that their retention of corporate clients and political candidates represents. But lobbying records and press accounts show that both firms represent numerous clients with business before the state and federal governments, a situation that raises questions, public-interest groups say, about the authenticity of the candidates’ policy positions.

“The conflict of interest arises because this is a business with its own agenda,” a lobbyist on campaign-finance issues with Public Citizen, a government watchdog group based in Washington, D.C., Craig Holman, said. “We can’t determine with any reliability that the Glover Park Group, for instance, is just going to promote the image of Hillary Clinton. They’ve got other high-paying clients that they certainly don’t want to chase away. They’re going to be advising Hillary Clinton in a manner consistent with the positions they’ve staked out.”

Groups like Public Citizen and the New York Public Interest Research Group have pressed for legislation that would increase oversight at these firms, but have been mostly resigned to underlining cases in which an apparent conflict is at play.

“The candidate is the person who is running for office, so it’s their responsibility to let the public know who is working for them,” Nypirg’s legislative director, Blair Horner, said. “I think there should be regulation. But in the absence of that, I think the candidate should be accountable for who they hire.”

According to lobbying records at New York’s state lobbying commission, the clients of Mercury Public Affairs this year included the Shinnecock Nation Gaming Authority, which wants to build a casino in Southampton, Long Island; the Jets football team, which was trying to win approval for a football stadium in Manhattan; the Distilled Spirits Council of the United States; the Natural Resources Defense Council; and Pfizer, the pharmaceuticals giant, among others. The lobbying commission list does not include the firm’s public-relations work or other non-lobbying activities.

Mercury’s clout at the state Capitol derives largely from the connections of its founder, Mr. Mahoney, a former official in the Pataki administration who has managed the governor’s campaigns. Another principal at the firm, Mr. McKeon, is a former communications director for Mr. Pataki and is now acting as campaign manager for Mrs. Pirro. Mr. McKeon is listed as the lead lobbyist in Mercury’s work this year for the Jets, which paid the firm $60,000 over a four-month period in the run-up to the stadium’s defeat at the hands of the state Legislature.

The Glover Park Group also registered as a lobbying organizing in New York this year, listing Madison Square Garden as its lone client. In a practice match-up between Glover Park, which is based in Washington, D.C., and Mercury, which is based in New York City, Madison Square Garden paid Glover Park $238,000 over a four-month period this year to fight the stadium. The upshot is that the same consulting firms that won big pay days on either side of the battle over the Jets stadium now stand to make even more money on opposite sides of the Senate race.

In addition to its work for corporate clients like News Corporation, Pfizer, Fannie Mae, the United States Telecom Association, the United Federation of Teachers, and the American Civil Liberties Union, Glover Park also retains foreign government clients such as the U.S.- Malaysia Exchange Association and the Embassy of Turkey, according to a report published earlier this year in the political newspaper Roll Call. Senate disclosure forms have the firm registered to lobby for Airbus Industrie, the European aerospace company; the Major League Baseball Players Association; Pharmaceutical Research and Manufacturers of America, the drug industry trade association; and the Recording Industry Association of America.

Because of her association with Mercury, Mrs. Pirro is not likely to make an issue of Mrs. Clinton’s work with Glover Park. Mrs. Pirro is also vulnerable to the charge of a potential conflict of interest, critics say, because her husband, Albert Pirro is a lobbyist with interests before the state Legislature. Pirro’s firm, the Pirro Group, lists clients ranging from the development company Forest City Ratner, to General Motors, the Greater New York Hospital Association, and several other not-for-profit health care associations.