After a slow start, the Obama administration's mortgage relief program has reached one in five eligible homeowners, a government report says.

More than 650,000 borrowers, or 20 percent of those eligible, have signed up for trials lasting up to five months, the Treasury Department says. The modifications reduce monthly payments to more affordable levels.

Launched with great fanfare in March, the plan got off to a weak start, but now nearly 920,000 loan modification offers have been sent to more than 3.2 million eligible homeowners. That works out to 29 percent, up from 15 percent at the end of July.

The next big challenge for the program is converting trial modifications to permanent ones. The government expects to release information on that later this month.