US President George W Bush has declared Friday 16 September a national day of prayer and remembrance for the victims of Hurricane Katrina.
Displaced people have already been receiving special debit cards
He asked agencies in the disaster zone to treat bodies with "dignity and respect", and announced initial aid of $2,000 (£1,090) for displaced families.
Mr Bush spoke as Congress approved a bill providing an additional $51.8bn (£28bn) for the relief effort.
Washington has been accused of reacting too slowly to the disaster.
Vice-President Dick Cheney has arrived in New Orleans as part of a tour of the south to review the progress of relief work.
Some 25,000 body bags are being sent to the city, where thousands are feared dead.
The floodwaters there, contaminated by chemicals and decaying bodies, are believed to contain high levels of E.coli and other bacteria.
Several deaths have been attributed to infected wounds, and the risk of disease outbreaks increases by the day.
But despite Mayor Ray Nagin's order to forcibly evacuate the city, some survivors are still refusing to leave.
Speaking at the White House on Thursday, Mr Bush announced that every family affected by Hurricane Katrina would receive the initial sum of $2,000 in aid.
He promised that the government would be with the survivors "for the long haul".
KATRINA'S CONFIRMED DEAD
Mississippi - 201
Louisiana - 83
Florida - 11
Alabama - 2
Georgia - 2
"We have many difficult days ahead, especially as we recover those who did not survive the storm," he said.
Government workers should, he added, "honour their memory by treating the dead with the dignity and respect they deserve".
Also on Thursday, a $51.8bn emergency package requested by Mr Bush was approved by the House of Representatives, and a few hours later by the Senate.
The funds, which come on top of $10bn granted last week, will be used mainly to pay for search and rescue operations, drinking water and medical assistance, officials said.
Mr Bush told Congress it should expect further emergency requests.
After a view of the damage in Gulfport, Mississippi, Mr Cheney flew by helicopter to New Orleans, arriving on an aircraft carrier docked in the Mississippi river where he was briefed on the situation.
He later visited the city centre to see the shattered floodwall on the 17th Street Canal.
The BBC's Justin Webb in Washington says his brief is to bang heads together and make sure that the things that went wrong in the early days of the relief effort are sorted out.
First Lady Laura Bush and Attorney-General Alberto Gonzales are also visiting the area.
Opinion polls suggest Americans are divided along political party lines in their judgement of Mr Bush's performance.
As water is pumped out of New Orleans, the diminishing flood reveals dead bodies, raw sewage, fuel and rusting vehicles.
Only 23 of the city's normal contingent of 148 pumps are in operation along with three portable pumps.
They are said to be pushing out about 60,000 gallons (228,000 litres) of water per second but water remains in about 60% of the city.