Steve Preston, secretary of Housing and Urban Development, said both private industry and government efforts have fallen short as the foreclosure crisis has exceeded all but the most dire forecasts.
"The response has not kept up with the need," Preston said in a speech the National Press Club. "Many Americans who should be getting help are not getting help."
The "FHASecure" program announced in August 2007 has only assisted about 4,000 delinquent borrowers and "has really not met the need," Preston said.
The other, called "Hope for Homeowners," has received just 111 applications from distressed homeowners since it was launched Oct. 1.
"Few lenders have actually signed up, and few borrowers are submitting applications," Preston said. "So clearly we needed to make meaningful changes."
Some experts have been skeptical of the efforts to curb foreclosures all along, saying they are too slow and reach too few homeowners, as CBS News correspondent Ben Tracy reported last week.
"It's like having a boat full of water that is leaking all the time and each one of these programs is like giving someone a cup to bail it out," Guy Cecala of Inside Mortgage Finance told CBS News. "We need to be using buckets."
The HUD chief outlined changes intended to encourage more participation in the Hope for Homeowners program, which refinances cash-strapped borrowers into new government-backed mortgages.
He also said that housing officials are reviewing whether additional changes to FHASecure might help that program gain traction.
Last week, hundreds of lenders gave HUD officials an earful of criticism about the Hope for Homeowners program. They blamed drawbacks in the program's original design for their lack of participation. Among their complaints: lenders were required to absorb large losses on the delinquent loans.
Under the new rules, lenders would be allowed to take a smaller loss. New loans can be made for 96.5 percent of the home's current value, rather than the previous level of 90 percent.
Even with the changes, borrowers would still have to pay back half of any appreciation back to the government if they sell their house or refinance.
The new guidelines only apply to borrowers who are spending up to 31 percent of their pretax income on their home loans. Borrowers who are spending a larger share of their incomes are required to have at least 10 percent in home equity.
Preston also said that lenders who hold home equity loans or other second mortgages must not block the transaction, but will receive an small payment and a share of any eventual appreciation in return for doing so.
In addition, lenders will be allowed to create new 40-year mortgages, rather than the traditional 30-year term, which will lower the borrowers' monthly payments but cost them more in interest over the life of the loan.
Rep. Barney Frank, D-Mass., chairman of the House Financial Services Committee, called the changes "very helpful steps and reflect a commitment to meeting the need for more aggressive action to diminish foreclosures."
However, consumer advocate John Taylor of the National Community Reinvestment Coalition said the changes "offer sweeteners for the lender and nothing for the homeowner."
Preston did not release updated projections of how many homeowners are expected to participate, but officials hope the new guidelines will help the program reach its original estimate of helping 400,000 distressed borrowers over the next three years.