Fannie Mae and Freddie Mac, the two government-controlled housing financiers, are gearing up for a flood of applicants wanting to refinance their mortgages under the government's housing market rescue plan.

President Barack Obama's housing plan is designed to allow 4m to 5m homeowners to refinance mortgages guaranteed by Fannie Mae and Freddie Mac, and could see up to $1,000bn of mortgages refinanced at lower interest rates.