For the first time, Congress has authorized Members and legislative branch agencies to offer “incentive” payments — worth up to $25,000 — to encourage employees to leave.

In return for a lump-sum payment, those who accept a buyout would essentially agree not to work on Capitol Hill for at least five years.

The measure was slipped into the massive omnibus spending bill that closed out the 108th Congress.

As written, the new law would appear to provide the buyout option for any Congressional employee who meets basic criteria. Actual terms, however, will not be known until key committees in the House and Senate have a chance to draw up rules for administering the payments.

“We’ll certainly review the language developed by the appropriators,” said Brian Walsh, a spokesman for the House Administration Committee. “But at this time there’s no timeline for establishing regulations.”

The legislative language lays down some basic principles. At bottom, only multiyear employees who are leaving voluntarily will be eligible to receive the one-time payments. The buyouts would not be available to contract workers or others whose positions are time-limited.

Sources familiar with their origins said the incentive payments were not aimed at encouraging lawmakers or Congressional agencies to cut staff.

“It’s a good-government thing,” said John Scofield, a spokesman for the House Appropriations Committee.

Scofield said the measure began as an effort to help the Government Printing Office, a Congressional agency, provide early retirement to a portion of its work force in fiscal 2004. Because appropriators had not authorized the agency to spend money from its own budget for the buyouts, Congress was forced to provide $10 million in supplemental spending to cover the difference.

With the language in the omnibus bill, the appropriators enabled GPO and other Congressional offices to buy out employees — if they see fit — using their own funds.

Appropriators had already provided similar flexibility to executive branch offices in 2002.

One senior House aide said he was “hard-pressed” to envision a situation in which a Member would seek authority to make such payments to a staffer. The staffer suggested the buyouts would likely apply only to Congressional agencies and support staff.

“Staff for individual Members of Congress serve at the will of the Member,” the aide said.

One Congressional legal expert, however, suggested that the buyouts may be useful to a Member as a mechanism that shields his or her office from a lawsuit that might be brought by a disgruntled former employee.

“You could say, ‘Settlement of all claims,’” when the payment is made, attorney Stan Brand said, who added that he had not seen the law as it was written.

Buyouts have long been common as a cost-cutting measure in the business world and in some parts of government, particularly at the municipal level. The measure enables managers to save money over the long term by convincing an employee to accept a large lump-sum payment — equal, perhaps, to a year or two of salary — and leave.

Unlike the typical corporate buyout, which is usually used to convince an employee to accept early retirement, the Voluntary Separation Incentive Payments, as the Congressional buyouts are technically known, work on a much smaller scale.

The Congressional buyouts, in any event, provide a disincentive to return, as much as an incentive to leave: Any employee who returns to Capitol Hill within five years of accepting the buyout must return the payment in full.