U.S. President Barack Obama is set to offer beleaguered American homeowners a chance to refinance their housing loans to take advantage of near-record-low borrowing costs.

White House officials described the plan in advance of Mr. Obama's announcement Wednesday at a community center outside Washington. They estimated that 3.5 million homeowners, many of whom hold loans that are bigger than the worth of their houses, could save about $3,000 annually by reworking the terms of their mortgages.

The average interest rate on 30-year home loans in the U.S. has for months been below 4 percent. But millions of homeowners have loans with higher rates and have not refinanced, in some cases because lenders have classified them as risky bets to repay the revised loans. Under the president's plan, some of those homeowners would be able to secure lower-cost loans.

Housing is the weakest sector of the American economy, the world's largest, and has been very slow to recover in the aftermath of the country's recession from 2007 to 2009. Millions of homeowners, many of whom had lost their jobs in the country's worst economic downturn in seven decades, have then had their houses repossessed by their lenders when they could no longer make their monthly loan payments.

Mr. Obama's plan will not help those who have already lost their homes, but could ease the financial burden for cash-short homeowners looking to cut their monthly bills.

The home loan plan could cost between $5 billion and $10 billion, financed by a tax on large banks, and would have to be approved by Congress. But Congress has already twice rejected similar proposals at a time when the country faces significant concerns about increased deficit spending.

Mr. Obama, a Democrat, is running for a second four-year term, with his handling of the country's economy a major concern for many voters. As the country's presidential election campaign has intensified, opposition Republican lawmakers and the party's presidential contenders have sharply criticized his economic leadership and have shown little interest in adopting his proposals.