The government plans to begin monitoring all telephone calls from federal offices this spring with a computer that will spot frequently dialed numbers, which officials say will uncover abuse of the phone system by U.S. employes.

Officials say the purpose of the program is to reduce the federal government's telephone bill by cutting down on personal calls. But critics say the audit creates a threat to the civil rights of federal workers, and Rep. Don Edwards (D-Calif.), chairman of the House subcommittee on civil and constitutional rights, has threatened to block the plan until he is satisfied about safeguards.

"This is Big Brother government collecting files on its employes and is ominous for civil rights," Edwards said. "The subcommittee is going to require the response to a number of questions."

"The whole emphasis here is trying to manage the telecommunications system," said Benjamin Friedman, acting deputy inspector general at the General Services Administration, which maintains the federal phone system. "We are trying to find means for managing the system and trying to find a systematic way to do it."

The telephone audit, which will last for an indefinite period, will be carried out by the President's Council on Integrity and Efficiency, comprising 17 inspectors general from federal agencies and headed by Joseph Wright, deputy director of the Office of Management and Budget.

Currently, each federal agency receives monthly phone company printouts of numbers dialed on their phones, but any action, such as an attempt to seek reimbursement from employes, is left to the discretion of supervisors, according to an OMB spokesman.

Now, however, the government will use a new tool -- computer software that can be programmed to cull specific information that will help spot potential abuse, Friedman said. "We are going to massage the information the phone company provides," he said.

The print-outs of phone numbers will be run through a computer equipped with software, yet to be developed, that will identify calling patterns.

The kinds of calls that would prompt attention by the computer include those to "Dial-a-Joke, Dial-a-Porn, Sports Highlights, calls to Atlantic City, Lake Tahoe or Florida resorts to make reservations, or collect calls," an OMB spokesman said.

Another tier of calls attracting attention because of potential abuse would be "calls to the same destination three times or more in a sample monthly billing period, calls placed at unusual times at night or on weekends, calls lasting more than 20 minutes, and, finally, when more than $500 has been spent on long-distance calls to one destination," the spokesman said.

Officials said the program, first outlined publicly in William Safire's column in The New York Times, will begin sometime after April. Precise timing will be kept secret so that employes will not be on guard, officials said.

"The audit will have a potentially chilling effect on whistle blowers in the government and will create a climate of distrust in the workplace," said Jerry Berman, legislative counsel to the American Civil Liberties Union.

"It raises more than civil liberties issues. . . . You can be more intrusive with respect to employes' behavior and use that to chill forms of expression and even creativity in government," he said.

An OMB spokesman insisted, however, that the program was not aimed at employes who might be calling reporters. "We view this as an attempt to track down misuse of property," not to spot whistle blowers, he said. "We will make sure agency auditors don't get into that."

Friedman contended the program is "perfectly legitimate and above-board," and said that privacy laws pertain to the dissemination of information to third parties, not the gathering of information.

"The privacy laws protect the release of such information -- if it is gathered for legitimate purposes, the laws do not affect that," he said. "The same information has been gathered in the past manually, the only difference is the same information is being gathered and manipulated by the computer."

The idea for the audit grew out of a review of the federal government's phone system begun last year by GSA. While GSA concentrated on locating phones and lines in disuse, it also was aware of abuse of telephone service, but was uncertain of the scope and cost to the government, GSA officials said.

They said some supervisors in government agencies are not seeking employe reimbursement for personal calls.

Some agencies, such as the Department of Energy, have taken legal action against employes who misuse the phone system, according to an official who did not want to be identified. The agency discovered 29 offenders at one of its offices in Washington state and recovered $38,000 in telephone service costs, the official said.

Each federal agency will decide what calling patterns it wants to examine, Friedman said. Agencies may decide they have the situation under control within a few months and can then limit auditing to an occasional schedule after that, he said.

The ACLU's Berman said the new power of computers in the exploding information age could easily be abused in such programs.

"The computer is giving government and business whole new ways of keeping track of behavior," at a time when "privacy laws are completely ineffective" against business or government access to records, he said.

"Congress has got to look at what is happening to privacy in the age of computers and start giving citizens some control over information kept in homes that now, to bank for example, you have to share with government and business entities," Berman said.