Administration officials said they oppose the bill's inclusion of $4 billion to help states buy and rehabilitate foreclosed properties, and a plan to have government-sponsored mortgage giants Fannie Mae and Freddie Mac fund the rescue.

They announced those and other objections as two GOP senators said they would try to block the package until a committee can investigate how much Countrywide Financial Corp. and other lenders stand to gain from it.

House and Senate Republicans voiced reservations about the bill in light of allegations that Senate Banking Committee Chairman Christopher J. Dodd (D., Conn.), one of its architects, and Senate Budget Committee Chairman Kent Conrad (D., N.D.), got cut-rate home loans through a VIP program at Countrywide, a subprime lender at the center of the mortgage meltdown.

Both said they neither sought nor knew about the special treatment.

Sen. Jim DeMint (R., S.C.) said, "This bill has come together in such a way as to raise questions all over this country that we need to answer before we move ahead."

The Senate rejected, 70-11, a move by DeMint and Sen. Jim Bunning (R., Ky.) to send the housing package back to Dodd's committee, which would have essentially killed the measure.

The election-year bill, which could help hundreds of thousands of struggling homeowners, appeared to be drawing wide bipartisan backing.

The Senate overwhelmingly defeated two amendments by Sen. Christopher S. Bond (R., Mo.) that would have derailed the bill. Both failed on margins large enough to override the promised veto.

One proposal, which failed 69-21, would have killed the foreclosure rescue. The other, defeated 77-11, would have essentially doomed an affordable-housing fund financed by Fannie and Freddie, leaving it, and the mortgage aid plan, with no source of money.

Dodd and Sen. Richard C. Shelby of Alabama, senior Banking Committee Republican, said the veto threat was "disappointing," given that their compromise plan includes several elements Bush has demanded, and said they hoped the White House would reconsider.

Democrats and many Republicans consider the housing measure a political imperative amid rising foreclosures and growing public anxiety about the sagging economy.

The centerpiece of the package is a foreclosure rescue program in which the Federal Housing Administration would provide $300 billion in cheaper mortgages for distressed homeowners who otherwise would be considered too risky to qualify for government-insured, fixed-rate loans.

Borrowers would be eligible if their mortgage holders were willing to take a substantial loss and allow them to refinance, and would ultimately have to share with the government a portion of any profits they made from selling or refinancing their properties.

A group of 28 House Republicans wrote to Speaker Nancy Pelosi (D., Calif.) yesterday demanding an investigation, with open hearings, on the Countrywide allegations.

Rep. Barney Frank (D., Mass) said his Financial Services panel would not look into Countrywide, given its full schedule and a pending Senate Ethics Committee probe.

Still, Frank and other Democrats have serious concerns about the Senate housing bill that could frustrate leaders' desire to send it to Bush before Congress breaks for a weeklong July 4 vacation.