WASHINGTON — The wealthiest Americans will not receive tax rebates under an economic stimulus plan advancing in the Senate, after senior lawmakers reinstated a cap on incomes that had been cut out of an initial proposal.

The change came after several senators, including the majority leader, Harry Reid of Nevada, protested the idea that the government would send $500 checks to millionaires as part of a package targeted to poor and middle-class families.

With the cap returned, the Finance Committee yesterday approved its own $157 billion economic stimulus bill, sending the legislation to the full Senate for a vote as early as today. The measure now proposes to phase out rebates for individuals making $150,000 or more a year, and families earning $300,000 or more. The caps remain twice as high as in a House stimulus package approved earlier this week, which would have phased out the rebates beginning at $75,000 for individuals and $150,000 for couples.

The ranking Republican on the finance panel, Senator Grassley of Iowa, said at a hearing yesterday that he had originally asked the committee chairman, Senator Baucus of Montana, to eliminate the caps after members of his party complained about “suffocating income limits.”

Opponents of the cut-off levels in the House bill cited the fact that in some areas of the country, including New York City, the caps would slash right through the middle class, potentially excluding many firefighters, police officers, and public school teachers. Eliminating the caps, Mr. Grassley said, would not just give rebates to “Bill and Melinda Gates” but to millions of American taxpayers. Ultimately, he said he agreed to a compromise of raising the income caps, but not scrapping them entirely. “From my perspective, this is a big improvement over the House bill,” he said.

Mr. Baucus said he talked to senators from both parties who pushed for the inclusion of the cap. The Senate stimulus also expressly bars members of Congress from receiving rebates, and it includes language aimed at curtailing checks to illegal immigrants — closing a loophole in the House bill that had already begun to spark a firestorm of protest from conservatives.

While several senators in both parties praised the new rebate cut-offs at the hearing yesterday, Democrats focused on other additions that they made to the House version of the stimulus, including more aid for low-income seniors and an extension of unemployment benefits. The Senate bill also adds more than $5 billion in energy tax credits, which costs a total of about $11 billion more than the House version for one year. The measure would send a flat $500 rebate to Americans who earn more than $3,000 a year, plus more than 20 million seniors who live entirely on Social Security. Couples would be eligible for $1,000, plus $300 for each child. President Bush is pushing Congress to move quickly on approving a stimulus package without loading it up with new spending projects. Mr. Baucus said yesterday he did not think the initiatives added by the finance committee would derail the bill, which must be reconciled with House leaders once it passes the full Senate.

Fears that the Senate could jeopardize the compromise struck last week by the House and the Bush administration appeared to have some effect at yesterday’s hearing, as lawmakers, including Senator Schumer, agreed to forgo amendments in the interest of quick passage.

“Speed is of the essence,” Mr. Schumer said. “You have to thread the needle here.”

He said he would support a second stimulus package advocated by many Democrats, which would include infrastructure spending projects, aid to states and localities, and measures to address the housing crisis. “I don’t this is the only bite at the apple,” Mr. Schumer said. “I do urge my colleagues to show some degree of restraint.” Senator Wyden, a Democrat of Oregon, made a forceful push for an immediate spending package for infrastructure projects, citing the support of Mayor Bloomberg, who called for a New Deal-style investment in infrastructure, such as bridges and roads, in a speech in Washington last week. Republicans and the White House have generally opposed such proposals for economic stimulus.

The Senate bill passed the committee on a bipartisan vote of 14–7, with some Republican senators criticizing the legislation as misguided. “Giving people tax rebates and telling them to go shopping will do nothing to stimulate the economy,” Senator Kyl of Arizona said.