Fed Chairman Ben Bernanke spoke of the much-awaited rules in a broader speech Tuesday about the challenges confronting policymakers in trying to stabilize a shaky U.S. financial system. To that end, Bernanke said the Fed may give squeezed Wall Street firms more time to tap the central bank's emergency loan program.

To prevent a repeat of the current mortgage mess, Bernanke said the Fed will adopt rules cracking down on a range of shady lending practices that have burned many of the nation's riskiest ''subprime'' borrowers - those with spotty credit or low incomes - who were hardest hit by the housing and credit debacles.

The plan, which will be voted on at a Fed board meeting on Monday, would apply to new loans made by thousands of lenders of all types, including banks and brokers.

Under the proposal unveiled last December, the rules would restrict lenders from penalizing risky borrowers who pay loans off early, require lenders to make sure these borrowers set aside money to pay for taxes and insurance and bar lenders from making loans without proof of a borrower's income. It also would prohibit lenders from engaging in a pattern or practice of lending without considering a borrower's ability to repay a home loan from sources other than the home's value.

''These new rules . . . will address some of the problems that have surfaced in recent years in mortgage lending, especially high-cost mortgage lending,'' Bernanke said.

Consumer groups have complained that the proposed rules aren't strong enough, while mortgage lenders worry that they are too tough and could crimp customers' choices.

Bernanke, in appearances on Capitol Hill said he doesn't believe taxpayers will suffer any losses.

In his speech Tuesday, the Fed chief defended those actions anew. If the Fed didn't intervene, he said, problems in financial markets would have snowballed, imperiling the country.