Obama had sketched out the proposals in his State of the Union address last week, including a tax on banks to pay for the plan that Republicans quickly rejected.
The White House offered more details on Wednesday ahead of a speech by Obama to expand on his initiative, which some Republicans have derided as an election-year ploy.
Nearly 11 million Americans are underwater on their mortgages, meaning they owe more than their homes are worth. Millions more have lost homes to repossession in states that will be up for grabs in 2012.
"While the government cannot fix the housing market on its own, the president believes that responsible homeowners should not have to sit and wait for the market to hit bottom to get relief," the White House said in a statement.
The White House is seeking to contrast Obama's stance with that of Republican presidential front-runner Mitt Romney, who has said US foreclosures should be allowed to run their course.
The next contest in the state-by-state battle for the Republican nomination is in Nevada, the state with the highest rate of foreclosure filings for the past five years.
The White House said the refinance program would be run by the Federal Housing Administration. The FHA has already been hard hit by rising defaults on mortgages it had insured, and its cash reserves reached a record low last year.
Many Republicans are likely to resist a larger role for the agency out of concerns taxpayers could be left on the hook for losses.
Obama's proposal, which needs congressional approval, would be open to borrowers who have been current on their payments for the last six months and have no more than one missed payment.