The lawsuit was filed in federal court in Washington, D.C., less than 24 hours after Bush administration officials announced the changes for the agency that merged 22 departments after the Sept. 11, 2001, terrorist attacks.
The unions charge that the new rules -- which will be implemented in phases beginning later this year -- removed DHS employees from longstanding rights to bargain collectively. The lawsuit asks the federal court to declare those regulations unlawful and to prevent their implementation.
"The employees losing their basic rights are the same men and women who guard our borders every single day," said Colleen Kelley, president of the National Treasury Employees Union. "There is absolutely no basis for stripping them of their rights while asking them to help keep America and our way of life intact."
NTEU and three other unions -- the American Federation of Government Employees, the National Association of Agriculture Employees and the National Federation of Federal Employees -- said in their lawsuit that the new rules would restrict appeals to independent boards that arbitrate labor disputes.
The lawsuit states that the new rules would prevent independent labor boards from easing penalties imposed on employees accused of misconduct.
DHS officials had no immediate comment on the union lawsuit.