A total of nearly 11,500 people were reported missing to the Find Family National Call Center, a center run by federal and state workers. The reports included people from throughout the Gulf Coast area, but most were from Louisiana.
All but about 3,200 had been located as of Wednesday, the agency said.
Also, after pressure from angry residents and a lawsuit, the city of New Orleans has agreed to notify owners before any hurricane-damaged home is demolished, even those homes washed into streets or reduced to heaps of debris.
Homeowners were outraged last month when a top official announced that 2,500 buildings had to be torn down within weeks because they posed an imminent threat to the public.
As for Katrina's missing, Dr. Louis Cataldie, the state's medical examiner, said he planned to ask state and parish officials to recheck about 400 addresses where authorities have consistent information about people missing from badly flooded neighborhoods. Most are in east New Orleans; about 50 are from St. Bernard Parish.
It's possible some of those missing were washed into Lake Pontchartrain, or their bodies remain in the rubble that still blankets much of the city. Over the last several weeks, at least one family returning to a wrecked home has found the remains of a relative inside.
Some of those still listed as missing likely have been found already by relatives but the center hasn't been notified of their status, the call center said. Others may not want to be found because of criminal or legal problems.
More than 1,300 Katrina-related deaths have been reported across five states, with 1,078 of those from Louisiana.
Meanwhile, a lawsuit was filed to stop the city from proceeding with its demolition plans, and on Dec. 28 the city agreed to put off any demolitions until the case could be heard in court.
On Friday, a federal judge approved a settlement between the city and plaintiffs that set up a notification system.
Under the agreement, homeowners of about 120 properties that were seriously damaged or pose an immediate threat to the public will be given seven to 10 days notice. A 30-day notice will be given to the owners of about 1,900 other houses slated for demolition.
Homeowners will be able to challenge demolitions.
"There are a lot of folks around town who I expect will protest," said Tracie Washington, a lawyer with the Washington-based Advancement Project, the advocacy group that championed the fight against the demolitions.
The city attorney's office did not immediately return a call seeking comment Wednesday morning.
Washington said the lawsuit was filed because many residents evacuated to other cities have not had a chance to go through their homes to find their possessions or because, in some cases, residents were still waiting for their insurers to assess their damage.
"I can't imagine coming back after being shipped off to another city and coming home and finding my home not there," Washington said.
The city has said that as many as 5,500 homes and businesses on the east bank of the Mississippi River may need to be razed.
Also Wednesday, Louisiana's top election official assured a federal judge that New Orleans can hold its hurricane-delayed elections by late April, and the judge gave the state a week to set the dates.
Gov. Kathleen Blanco postponed the Feb. 4 elections for mayor, City Council and other posts after Katrina scattered most of the city's half-million residents and damaged hundreds of election precincts.
Secretary of State Al Ater told U.S. District Judge Ivan Lemelle that the primary could be held on April 22 and a general election on May 20.