The Obama administration wants to raise fees for borrowers and require larger down payments for home loans as part of a long-term effort to restructure the nation's housing market. But it warned that these measures could boost mortgage rates and make it harder for home buyers to secure the 30-year fixed-rate mortgage, a mainstay of American home buying for decades.

In a long-awaited white paper, the administration said it intends to wind down the federal mortgage giants Fannie Mae and Freddie Mac and curtail the Federal Housing Administration to help reduce the government's outsized role in mortgage funding.

The housing finance system, which has ensured that Americans can get home loans, came crashing down in the financial crisis, helping fuel millions of foreclosures and the recession.

"I think it's absolutely the case that the U.S. government provided too much support for housing, too strong incentives for investment in housing," Treasury Secretary Timothy F. Geithner said Friday during a speech at the Brookings Institution. He noted that in addition to those fundamental mistakes, the government "allowed a huge amount of basic mortgage business to shift where there was no regulation or oversight."

But in proposing a strategy for the future, administration officials acknowledged they are walking a tightrope. Any steps that dial back government support too dramatically - making mortgages more expensive - could extend the housing decline.

Geithner said that a new housing finance system without Fannie and Freddie could take seven years to put in place, suggesting it might fall in part to future administrations.

"We have to see the process of repair in the housing market completed," Geithner said.

The white paper focuses on a series of short steps to increase fees and down-payment requirements. The administration hopes these measures will allow banks to more effectively compete in offering loans without government guarantees.

The report offers three options for replacing Fannie and Freddie. They include creating a new government agency that would continue to insure mortgages or a new agency that would step in only during times of crisis. Each, however, could put taxpayers at more risk of having to bail out the mortgage market during big declines.

The most drastic option would end government backing for home loans beyond the FHA. But the administration warned that this measure could affect access to credit for many potential homeowners. It could boost mortgage rates the most, the officials said, and it could make it harder for community banks to compete in the housing market.

In not offering a single long-term vision for the housing finance system, the administration sought to avoid a contentious clash with Republicans, who often have portrayed the mortgage giants as the chief culprit in the financial crisis. Republicans are likely to agree with the administration's plan to reduce taxpayer support for mortgages over time.

But Rep. Spencer Bachus (R-Ala.), the new chairman of the House Financial Services Committee, said in a statement that while the proposal includes elements that GOP lawmakers have embraced in the past, it "isn't a plan to move us forward, but rather a collection of opinions to consider. What's needed is a real plan, and we intend to sit down with administration officials to find common ground ... we need legislation that protects taxpayers from further losses and future bailouts and builds a stable housing finance system based on private capital."