WASHINGTON — In the two months since it launched, the Obama administration's foreclosure prevention plan has outperformed the government's previous attempts, offering more than 50,000 homeowners lower-cost mortgages.

Yet the $75 billion program, known as Making Home Affordable, has been implemented unevenly by lenders, leaving some homeowners frustrated and bewildered.

The demand from distressed borrowers has overwhelmed many lenders and nonprofit organizations, which have hired more staff to cope. And there is a growing concern about whether the plan can reach its goal of helping 4 million homeowners without tackling the issue of borrowers who owe more than their home is worth.

"The program on paper is excellent," said Bruce Dorpalen, director of housing counselors at Acorn Housing, a nonprofit group. But "implementation has been very slow. We're holding thousands of deals right now so they can be reviewed. Most servicers are only partially up and running."

Last week, Fannie Mae, the government-controlled mortgage financing company, obtained a temporary restraining order from the South Carolina Supreme Court to stop the foreclosure sale of more than 1,000 properties there so it could give the program more time to work.

The Treasury Department is still finalizing parts of the program. Treasury Secretary Timothy Geithner last week released details of a $10 billion insurance plan that will help shield lenders from losses associated with falling home prices. He also announced plans to offer incentives to lenders that help borrowers sell their homes for less than they owe.

"We have been incredibly encouraged by the pace of servicer participation," said Jenni Engebretsen, a Treasury spokeswoman. Lenders representing 75 percent of U.S. mortgages have already agreed to participate, she said. "We are reaching more and more families, and the launch trajectory is quite promising."

Others think it's still too early.

"The jury is still out," said Guy Cecala, publisher of Inside Mortgage Finance Publications. "It is showing some potential. But they are not keeping pace with the number of loans that are going into foreclosure."

THOUSANDS HELPED

The program works by paying lenders to reduce homeowners' payments by lowering their interest rate and extending the length of their loan. About 55,000 homeowners have been offered modified loans, according to the administration official. At least 20,000 homeowners are already making lower payments, according to interviews with major lenders and mortgage servicers. In comparison, only one homeowner has received a loan under Hope for Homeowners, the government's previous major attempt to arrest foreclosure rates launched in October. Another government program, FHASecure, refinanced only about 4,000 of the subprime borrowers it targeted before expiring at the end of last year.

Florida-based Ocwen Financial, which services about 300,000 subprime loans, has offered about 35,000 modifications under the program. J.P. Morgan Chase has modified another 15,000. Bank of America said "thousands" of loans have been modified under the program. Yet some homeowners are still in limbo.

Bethesda, Md., resident Konrad Stutzmann, 39, initially asked GMAC Mortgage to modify the loan on his one-bedroom condo in January after he lost his sales job and secured a lower-paying position elsewhere. But Stutzmann said he was told that modifications were being offered only to borrowers who had missed two payments. When the Obama administration launched its program in March, he tried again. But, more than two months later, he has not received a response.

Meanwhile, Stutzmann said, his credit score has taken a hit and his credit card limits have been lowered or canceled. He has missed a few payments on the mortgage and dipped into his savings to keep up with bills and catch up with the home loan.

"I would love it if they could just lower my interest rate for just a couple of years, like three years," he said. "I am hoping by then things will be looking better. But they are dragging their feet."

GMAC Mortgage says it has approved 1,750 mortgage modifications under the administration's program and is hiring 300 to 400 people answer homeowners' calls.

IMPERFECT PLAN

The program has been implemented unevenly. Houston-based Litton Mortgage Servicing, which handles about 400,000 mortgages, has not begun modifications under the program. HSBC has begun modifying loans that it services for Fannie Mae and Freddie Mac under the program but not loans in its own portfolio.

"We are in the process of evaluating the administration's plan for this portfolio of customers," the company said in a statement.

There is also growing concern that the plan doesn't do enough for borrowers who owe more than their home is worth, known as being underwater.

Those homeowners are helped under a separate part of the housing program, which lets them refinance even if they have little or no equity in their home. Thousands have received refinanced loans under the program, according to Fannie Mae and Freddie Mac.

But the program is limited to borrowers who owe no more than 105 percent of the value of their home and have a loan backed by Fannie or Freddie. According to research company FirstAmerican CoreLogic, about 1 million homeowners with loans backed by those firms are too far underwater to qualify.

And while homeowners can reduce their payments under the program, it will not affect how much they owe for the house. Home values are expected to continue to fall through this year, pushing more people underwater and putting them at higher risk of foreclosure.