''The current regulator does not have the tools, or the mandate, to adequately regulate these enterprises,'' Mr. Oxley said at the hearing. ''We have seen in recent months that mismanagement and questionable accounting practices went largely unnoticed by the Office of Federal Housing Enterprise Oversight,'' the independent agency that now regulates the companies.

''These irregularities, which have been going on for several years, should have been detected earlier by the regulator,'' he added.

The Office of Federal Housing Enterprise Oversight, which is part of the Department of Housing and Urban Development, was created by Congress in 1992 after the bailout of the savings and loan industry and concerns about regulation of Fannie Mae and Freddie Mac, which buy mortgages from lenders and repackage them as securities or hold them in their own portfolios.

At the time, the companies and their allies beat back efforts for tougher oversight by the Treasury Department, the Federal Deposit Insurance Corporation or the Federal Reserve. Supporters of the companies said efforts to regulate the lenders tightly under those agencies might diminish their ability to finance loans for lower-income families. This year, however, the chances of passing legislation to tighten the oversight are better than in the past.

Reflecting the changing political climate, both Fannie Mae and its leading rivals applauded the administration's package. The support from Fannie Mae came after a round of discussions between it and the administration and assurances from the Treasury that it would not seek to change the company's mission.

After those assurances, Franklin D. Raines, Fannie Mae's chief executive, endorsed the shift of regulatory oversight to the Treasury Department, as well as other elements of the plan.

''We welcome the administration's approach outlined today,'' Mr. Raines said. The company opposes some smaller elements of the package, like one that eliminates the authority of the president to appoint 5 of the company's 18 board members.