WASHINGTON —  A consumer-rights group on Tuesday challenged as unconstitutional the Deficit Reduction Act that cuts a wide variety of federal programs, on grounds the version President Bush signed differs from what was passed by the House.

The lawsuit by Public Citizen in U.S. District Court here is the second filed after Bush signed the $39 billion deficit-cutting legislation into law on Feb. 8. A Republican activist also has sued in federal court in Alabama.

"Under the Constitution, the same version of a bill has to be passed by both houses of Congress," said Adina Rosenbaum, an attorney at Public Citizen. "We filed our lawsuit because it's important for the government to abide by the law."

The lawsuit seeks to throw out the law entirely, requiring Congress "to start again from square one," Rosenbaum said. The group is seeking the court's expedited consideration, although it acknowledged that the process could take several months.

At issue is a provision involving how long Medicare pays for renting some types of durable medical equipment. The Senate voted for 13 months, as intended by Senate and House negotiators, but a Senate clerk erroneously put down 36 months in sending the bill back to House for a final vote, and that's what the House approved Feb. 1.

By the time the bill was shipped to Bush, the number was back to 13 months as passed by the Senate.

House Democrats have accused GOP leaders of abusing the legislative process and asked for another vote. GOP leaders have declined. On the Feb. 1 vote, the bill passed by the slimmest of margins, 216-214.

Under court rules, a plaintiff must show it suffered specific harm in order to have the standing needed to file suit. The lawsuit in Alabama was filed by Jim Zeigler, a lawyer who advises the elderly on eligibility for nursing home care under the Medicaid program for the poor and disabled.

Public Citizen said it was harmed by a separate portion of the budget bill — which was consistent in both House and Senate versions — that increases court filing fees.