As corporations in the post-Enron era are pushed to monitor and disclose more of their activities, some executives warn that the effort could backfire by hurting the most vigilant of the companies, and they are asking the government for protection.

"Vigilant self-policing can create a documentary 'roadmap' that can be used against a company," John T. Bentivoglio, a lawyer who represents 19 pharmaceutical companies, including Merck & Co., Pfizer Inc. and GlaxoSmithKline PLC, wrote in a recent letter asking the U.S. Sentencing Commission to change guidelines regarding internal probes.

"When companies undertake rigorous" self-evaluations, "there is no guarantee that the information generated will not be used against them in various legal proceedings, both criminal and civil," David Greenberg, senior vice president of Philip Morris Cos., the corporate parent of the cigarette maker and Kraft Foods Inc., wrote in comments to the commission also suggesting ways to protect companies.

An advisory board to the U.S. Sentencing Commission is to hold hearings today on whether federal sentencing guidelines discourage extensive self-monitoring and, if so, whether they should be changed.

Underlying much of the guidelines is the idea that defendants who work with the government should get some leniency. But prosecutors often demand access to internal investigations before recommending reduced sentences.

Corporations are pushing to have the guidelines explicitly state that such disclosure is not required to get leniency.

Those efforts are expected to be opposed by prosecutors. "I guarantee you that prosecutors will fight such a proposal to the end," said Michael E. Horowitz, a former chief of staff of the Justice Department's criminal division and member of the sentencing panel's advisory board.

Prosecutors believe "that companies seeking a pass from prosecution should not be automatically entitled to credit for cooperation despite refusing to produce an internal investigation," said Horowitz.

The U.S. Sentencing Commission, which has seven voting members appointed by the president, is an independent agency that establishes parameters used by federal judges during sentencing.

The 16-member advisory board, made up of defense lawyers, prosecutors and ethics experts, was appointed by the Sentencing Commission to make recommendations, due next year, on whether and how guidelines for corporate crimes should be revised.

The ideal of using internal investigation against companies is not new. What is new is that -- after a series of financial scandals -- there is increased public and government pressure for corporations to police themselves and disclose the results.

Some companies have, in the past, opted for oral reports rather than written ones to protect themselves. Others have tried to make investigations so lax that only the most egregious acts were caught, although new federal corporate monitoring and certification requirements may make that more difficult.

Some companies have tried to keep internal investigations from prosecutors by hiring their law firms to conduct the probes and then citing attorney-client privilege. But prosecutors often ask companies to waive that right. The guidelines are silent on whether companies must waive the right if they want to receive a mitigated sentence.

"I think that in the current climate, companies need to assume an internal audit could and would be used against them," said Lisa A. Kuca, another member of the Sentencing Commission's advisory board and director of corporate compliance for H&K Investigative Solutions LLC, an arm of Holland & Knight Consulting LLC.

Columbia Healthcare learned that when the government accused it of grossly overcharging for Medicare and Medicaid service in the mid-1990s. At first, the company refused to give the Justice Department internal audits of its billing practices, citing attorney-client privilege.

The company reached a settlement with Justice, agreeing to release the documents to the government, but only under a strict confidentiality agreement. A federal judge, however, threw out the pact, saying the attorney-client privilege could not be partially waived, and made the audits publicly available.

A few industries have managed to win some protection. Doctors, for example, judge one another's work in a confidential process called medical peer review.

In the mid-1990s, 27 states passed laws protecting the confidentiality of internal environmental audits after intense lobbying by groups such as the American Chemistry Council. The Environmental Protection Agency, which has opposed the effort, said the laws have permitted companies to engage in legal coverups.

"Privileges are not a good thing as a policy matter," said Bertram C. Frey, deputy regional counsel for the Environmental Protection Agency in Chicago.

Bentivoglio, in his written comments, countered that if the government can "refrain from seeking documents that only exist because of the voluntary efforts at self-scrutiny," the sentencing panel can strengthen the efforts of corporations by reducing the risk that they will be penalized for self-policing.