Washington  - The United States launched an effort Wednesday to help homeowners pay off their mortgages, hoping to stabilize a housing crisis that lies at the centre of the country's deep recession.

President Barack Obama last month announced a 75-billion-dollar plan to help up to 9 million homeowners refinance their mortgages and avoid foreclosure.

The US Treasury announced the specifics Wednesday that will help private lenders ease the burden on struggling homeowners. Under the plan, the government could subsidize deals reached between lenders and mortgage holders to lower their monthly payments.

The Treasury will also expand refinancing efforts by government- chartered lenders Fannie Mae and Freddie Mac, which together own or guarantee about half of all US mortgages.

The new measures are designed to halt an unprecedented number of foreclosures - more than 3 million in 2008 - that brought the US financial sector to the brink of collapse as firms lost hundreds of billions of dollars in mortgage-related investments.

"It is imperative that we continue to move with speed to help make housing more affordable and help arrest the damaging spiral in our housing markets," Treasury Secretary Timothy Geithner said in a statement.

US home prices have fallen nearly 20 per cent over the past year since a decade-long housing bubble came to an end. As a result, millions of homeowners owe more on their mortgages than their property is worth, preventing them from refinancing or selling the house if they can no longer afford the payments.

But Obama's plan came under fire from some conservatives for potentially rewarding homeowners and speculators that knowingly took on more than they could handle.

According to the new details released by the Treasury, homeowners would have to prove "financial hardship" before getting access to government aid. (dpa)