WASHINGTON — Treasury Secretary Henry Paulson said Monday that an agreement was near on a proposal to help thousands of at-risk homeowners avoid foreclosures by temporarily freezing their mortgage rates.

One of the last remaining issues to be resolved, officials said, was the exact length of time the low-teaser rates will be frozen.

Paulson expressed optimism that an agreement could be reached very soon, possibly before the end of this week.

He and federal regulators have been holding talks with some of the country's biggest banks, mortgage investors and consumer groups trying to strike a deal in an effort to prevent an avalanche of threatened foreclosures in the coming year from sinking the overall economy.

"We are working aggressively and quickly, utilizing available tools and creating new ones, to help financially responsible but struggling homeowners," Paulson said in a speech to a national housing conference.

An estimated 2 million subprime mortgages, loans offered to borrowers with spotty credit histories, are scheduled to reset to much higher levels by the end of 2008. Those resets will push the payment on a typical mortgage up by $350 per month, taking it from $1,200 to $1,550.

Some government regulators are pushing for the low "teaser" rates to remain in place for five to seven years, arguing that a longer period of time is needed to allow the depressed housing market to begin recovering and for home prices to stabilize, which will allow homeowners to finance under better terms.

But investors, who will see lower payments on the loans, are arguing for a shorter period of time.

Regulators indicated that the rate freezes will only be available for owner-occupied homes to avoid granting the break to real estate speculators although the exact way that determination will be made is still being worked out.

"How you structure (the rate freeze), who gets it and for how long, I think, is what people are struggling with," Comptroller of the Currency John C. Dugan, said at the conference.

Sheila Bair, chairwoman of the Federal Deposit Insurance Corp., said details of the plan are likely to be announced later this week with other officials predicting the unveiling could come Thursday.

In his speech, Paulson said he believed the mortgage industry would move to implement the new program quickly and would also adopt benchmarks to measure progress going forward.

"As a result, what was a fragmented, cumbersome process can be a coordinated effort which more quickly helps able homeowners," he said.

Banking industry executives generally praised the initiative. Daniel Mudd, chief executive at Fannie Mae, the nation's largest provider of home mortgages, called the proposal a positive step that would allow many borrowers to avoid foreclosure.

The program is aimed at homeowners who have steady incomes and relatively clean repayment histories who could afford lower introductory mortgage rates but not the higher adjusted rate.

Paulson also called on Congress to pass a number of pending bills that would address the housing crisis in such ways as expanding the availability of Federal Housing Administration insured loans and boosting government oversight of mortgage giants Fannie Mae and Freddie Mac.