Under a court order, the Bush administration will restart a housing program for Hurricane Katrina victims early this week and begin explaining to thousands of evacuees why their aid was cut off this summer.

U.S. District Judge Richard Leon ruled last month that the Federal Emergency Management Agency violated the Constitution when it eliminated short-term housing assistance and provided victims only confusing computer-generated codes to explain its decision.

FEMA officials testified in court Monday that the agency could restore the system this week but did not say how soon Texas officials could begin receiving money to cover housing for Katrina evacuees — about $750 a month per family. Officials also said they were working to produce easily understandable letters from an outdated computer system to explain why the aid was eliminated and how to appeal the decision.

“Maybe we can get this thing jump-started and get these people a roof over their heads before Christmas,” said Leon, who first ordered the agency to comply three weeks ago.

James Walke, a FEMA section chief, originally testified that it would take until Friday to prepare documentation to restart the program. When he told Leon the documentation was only two pages, Leon pressed to get it finished by Tuesday afternoon and Walke said he would.

That puts FEMA in a potentially awkward position. The agency is challenging Leon’s ruling and has asked an appeals court to delay enforcement of his order until the case is resolved. That order likely won’t come until the middle of the week at the earliest.

By then, FEMA will have advised Texas officials that they plan to restore housing funding and many evacuees may have received letters. If FEMA prevails at the appeals court, officials will have to turn around and tell those people they are once again without aid.

Even if the appeals court upholds Leon’s order, however, the aid program is still temporary. Leon only ruled that FEMA must make payments until it can adequately explain why the program was eliminated and give victims a chance to appeal.

Once that happens, evacuees likely will be cut off again if they cannot prove they meet the criteria for continued aid.

Leon has also ordered FEMA to make three months of retroactive housing payments, which would amount to checks of about $2,250 for each eligible family. FEMA now estimates 4,200 Texas families are covered by Leon’s order.

Margaret A. Young, the agency’s CFO, said the agency is unable to make the retroactive payments, which would amount to about $10 million. The short-term housing program was set up to reimburse local governments for the cost of housing evacuees, she said, not to make direct payments to victims.

Brian Verburg, the chief of FEMA’s National Processing Service Center in Virginia, testified that the agency’s computer system was not designed to produce letters in plain English, only in program codes. He said officials are working long hours to get the letters out.

“We may make mistakes occasionally but we’re not a bunch of people sitting around just dragging our feet,” Verburg said.