A group of federal employee unions said they will sue to block new Department of Homeland Security (search) personnel rules that the unions said would strip workers of essential collective bargaining rights.

The rules, unveiled by the agency Wednesday after more than a year of negotiations, would violate the 2002 law creating the department, union officials charged.

The regulations include adopting a pay-for-performance system and building an internally run labor review board (search) to oversee employee labor relations, among other changes from standard federal personnel policies.

While the unions said they were satisfied with certain aspects of the new rules, other changes will "irreparably impair the ability of DHS to retain the experienced employees it has today and recruit a top-notch workforce in the future," said National Treasury Employees Union (search) President Colleen Kelley in a prepared statement.

Her union, along with the American Federation of Government Employees (search), the National Association of Agriculture Employees (search) and the National Federation of Federal Employees (search), is expected to jointly file a lawsuit against the department and the U.S. Office of Personnel Management (search).

But a Homeland Security spokesman said labor unions had a "big part" in the final version of the personnel rules released Wednesday.

"The unions were brought in early on" in the process, said spokesman Larry Orluskie.

But Charles Showalter, president of the homeland security subdivision of AFGE, said in a statement that the agency ignored its employees' concerns about the changes, concerns that were communicated both directly and through union surveys.

Orluskie declined to comment on the threat of a lawsuit until one is filed.

In a prepared statement, the department defended the new rules, saying that standard federal civil service policies would have been "outmoded and unresponsive" for an agency like Homeland Security. Orluskie said the changes will be phased in gradually over at least the coming year.

"We want to be slow, cautious, make sure we're doing the right things along the way," he said.

The rules brought a swift response from Rep. Steny Hoyer, D-Md, the House minority whip. He said he was "particularly troubled" that the changes would curtail thousands of employees' bargaining rights and subject them to a "new and untested" pay system.

"I will not hesitate to take appropriate action if the new system poses problems, by urging the Congress to make changes to the rules," Hoyer said in a written statement.

Capital News Service contributed to this report.