WASHINGTON — A bipartisan Senate bill designed to ease the slumping housing market won tepid reviews yesterday, and even its top sponsor acknowledged that much more is needed to help millions of families threatened with foreclosure.

The scaled-back proposal unveiled by the chairman of the Senate Banking Committee, Christopher Dodd, a Connecticut Democrat, contains an amalgam of ideas aimed at boosting demand for housing and helping homeowners saddled with subprime mortgages avoid foreclosure.

The plan contains $4 billion in grants to local governments to buy and refurbish foreclosed homes, new authority for states to issue bonds to be used to refinance subprime mortgages and a temporary $7,000 tax credit for people buying new homes or properties in foreclosure.

Those provisions, and others, were the product of a bipartisan negotiation that produced a narrow, common-denominator approach to the crisis.

“There’s a lot more that needs to be done,” Mr. Dodd said. “But it’s a step in the right direction.”

The White House weighed in with serious doubts about the plan and economists across the spectrum are skeptical that it do much to ease the wrenching crisis in the housing market and the wave of foreclosures spreading across the country.

A spokesman from the White House, Tony Fratto, said the administration likes some provisions, such as issuing mortgage bonds and modernizing the Federal Housing Administration to boost access to FHA-insured loans. But he added that the administration has “serious concerns” about other provisions such as the homebuyers’ tax credit and aid to local governments to purchase foreclosed homes.

“Some of these provisions that are purportedly to help homeowners actually would not help them and in some cases could hurt them,” Mr. Fratto said. For example, he said, the tax credit for buyers of foreclosed and newly constructed homes could force down prices for many other sellers.

While supporters said the measure would boost demand for housing, help people refinance adjustable-rate mortgages and help communities beset with abandoned homes, many economists cautioned that the measure’s benefits would be modest — and would help banks and homebuilders while doing hardly anything for people facing foreclosure.

“They’re good steps, but they’re small steps and certainly not big enough steps to solve the problem,” the chief economist for Moody’s Economy.com, Mark Zandi, said. “I don’t think it’s going to be enough to solve the housing problem, at least not in 2008.”

The measure also contains a provision dropped from February’s stimulus measure that would permit home-builders and other money-losing businesses to reclaim previously paid taxes, new disclosure requirements aimed at preventing unsophisticated borrowers from being duped by mortgage brokers, and additional money to provide counseling to people threatened with foreclosure and help them in negotiating with their lenders.

Republicans forced Democrats to drop efforts that Mr. Zandi and other economists said might have proven more effective in alleviating the crisis, including a controversial plan opposed by banks and their Republican allies to change bankruptcy laws to help borrowers trapped in subprime mortgages keep their homes.

Mr. Dodd was also forced to leave out of the bill a plan to have the Federal Housing Administration guarantee perhaps $400 billion worth of refinanced loans if lenders reduce loan amounts to reflect reduced home values. Mr. Dodd told reporters he would continue to work on the idea in hopes of advancing it later in the year.

Republicans won a scaled-back version of a plan by Senator Isakson, a Republican from Georgia, to provide a temporary tax credit to people buying foreclosed or newly built homes. Mr. Isakson sought $15,000 in tax credits spread over three years — aimed at boosting demand in the slumping housing market — but GOP negotiators settled for a $7,000 credit awarded over two years.