CHICAGO (Reuters) - A new policy on mortgage down payment requirements from Fannie Mae (FNM.N: Quote, Profile, Research) is "sound," and could help unleash pent-up demand, James Lockhart, director of the Office of Federal Housing Enterprise, said on Friday.

"There is pent-up demand for housing," Lockhart told reporters after a speech at the Federal Reserve Bank of Chicago's bank structure conference.

"Maybe people are thinking that now is the right time to get a mortgage."

Fannie Mae on Friday announced a new, national policy on downpayment requirements for conventional, conforming mortgages.

The guidelines supercede more stringent requirements adopted in December, requiring higher downpayments in markets where home prices are falling.

"It's still sound underwriting and makes sense in this type of market," Lockhart said. "They're doing it in a controlled and good manner ... they are trying to help people get into houses."

Lockhart also said components of the Senate Banking Committee's housing bill that touch on the government-sponsored enterprises, or GSEs, regulated by OFHEO, "look like a good, solid bill."

"Hopefully they'll vote on Tuesday and get moving on this," Lockhart said. "If they can't get the legislation done now, then when?"

Earlier, in prepared remarks, Lockhart said said Fannie Mae and Freddie Mac (FRE.N: Quote, Profile, Research) remain "a point of vulnerability to the financial system" because they are so highly leveraged relative to their level of risk.