WASHINGTON (AP) — Rates on 30-year fixed-rate mortgages fell to a record low for the second straight week, causing refinancing applications to surge to the highest level in more than five years, a month after the Federal Reserve pledged to channel billions to prop up the sinking U.S. housing market.

While homeowners around the country are taking advantage of historically low rates to refinance their loans, the opportunity isn’t available to those with poor credit or little equity in their homes, and foreclosures are still likely to surge.

Freddie Mac, the mortgage company, reported Wednesday that average rates on 30-year fixed-rate mortgages dropped to 5.14 percent last week, down from the previous record of 5.19 percent, set the previous week. The rate was the lowest since Freddie Mac’s weekly mortgage rate survey began in April 1971 and the eighth straight week of declines.

At Signature Home Funding in Winter Haven, Fla., traffic nearly doubled the previous week from two weeks ago as borrowers moved to refinance into the lower rates, said mortgage broker Kevin Sandridge.

“We’re seeing a lot of activity on [refinancing] right now,” Sandridge said, noting he was quoting clients a rate as low as 5.87 percent for a 30-year, fixed mortgage, including fees.

To qualify, however, borrowers generally must have a FICO score of at least 600, he said.

“Below 600 is doable, but not below 580,” Sandridge said.

Mortgage rates started falling after the Federal Reserve launched a sweeping new effort in late November to aid the U.S. housing market by purchasing up to $600 billion of mortgage-related securities and other debt issued by Fannie Mae, Freddie Mac and the Federal Home Loan Banks.

Last month, the Fed, aiming to free up lending and jolt the economy back to life, cut its key interest rate from 1 percent to a target range of zero to 0.25 percent and pledged to keep funneling money into the market for mortgage investments.

Meanwhile, the Mortgage Bankers Association said Wednesday its application index surged 48 percent in the week ended Dec. 19 to 1245.5. Total applications and refinance activity were at their highest levels since July 2003, when refinancing boomed at the peak of the housing market.

More than 80 percent of applications came from borrowers looking to refinance into loans with more affordable rates, the trade group said.

The average rate on a 15-year fixed-rate mortgage dropped to 4.91 percent from 4.92 percent the previous week, Freddie Mac said.

Rates on five-year, adjustable-rate mortgages fell to 5.49 percent, compared with 5.6 percent the previous week. Rates on one-year, adjustable-rate mortgages rose to 4.95 percent, from 4.94 percent the previous week.

The rates do not include add-on fees known as points. The nationwide fee for 30-year mortgages averaged 0.8 point the previous week, compared with 0.7 point for 15-year mortgages.

The fee on five-year, adjustable-rate mortgages averaged 0.6 point, while the fee on one-year adjustable-rate mortgages averaged 0.6 point.

Meanwhile, with 2008 home sales falling to the lowest point in at least 10 years, housing industry lobbyists are pressing in Washington for further aid to the housing market. Homebuilders want tax credits of up to $22,000 for home purchases and subsidies that would bring mortgage rates to as low as 3 percent for the first half of next year.

“It’s just a matter of some spark,” David Crowe, chief economist at the National Association of Home Builders said Tuesday. “The consumer is looking for some signal that now is the time.”