WASHINGTON - Federal contractors caught hiring illegal immigrants would be banned from government work for up to a decade under sanctions the Senate added unanimously to a minimum-wage bill.

Yesterday's action, pushed by Republican senators, was this Congress' first foray into immigration regulation, and it prompted an outcry of opposition from business groups.

By a vote of 94-0, the Senate approved an amendment by Sen. Jeff Sessions (R., Ala.) that would impose a contract ban on companies, even if they hired illegal workers inadvertently, from seven to 10 years. The ban would not be subject to appeal in court, but the federal government could waive it for national security reasons.

Companies that use a pilot electronic employment verification system would be exempt from the sanctions.

Whether the provision survives final passage of a minimum-wage bill remains a question. The House minimum-wage legislation has no additional provisions, and the Senate language could be stricken when the bills are reconciled.

Both chambers' bills would raise the federal wage floor from $5.15 to $7.25 an hour.

Yesterday's vote came just one week after immigration officials arrested 40 illegal workers hired by military contractors in three states.

"The vast majority of businesses carefully follow the law, but many of them unfortunately do not," Sessions said. "Some are even contractors who are working on sensitive government contracts. Let me tell you, we have a problem."

Over the last year, immigration officials have put a priority on cracking down on illegal workers at military installations and other places considered critical to national security.

But business groups mobilized yesterday to try to kill Sessions' amendment, saying its reach would go far beyond military contractors and military installations. Jeffrey D. Shoaf of the Associated General Contractors of America compared it to "using the nuclear option for a paperwork violation."

Among the critics were the American Meat Institute. Over the years, meat-packing plants have been frequent targets of immigration raids. Others who signed on to a letter of opposition included the U.S. Chamber of Commerce, the National Association of Homebuilders, and the Associated Builders and Contractors.

Critics objected that the provision did not give businesses the opportunity to appeal the ban in court and said the national security waiver would place small businesses at a disadvantage.

Earlier yesterday, the Senate defeated an effort to require every state to raise its minimum wage by $2.10 an hour, even if a state's minimum exceeds the federal wage floor. Democrats said the Republican proposal was designed to kill the underlying minimum-wage legislation.