US President Bush has again promised that the government will learn from mistakes made during Hurricane Katrina.
The first anniversary of Katrina is already being marked
More than 1,000 people were killed when the hurricane struck the Gulf Coast of the US almost a year ago.
In his weekly radio address the president said the disaster has exposed deep-seated poverty and a lack of readiness to deal with the crisis.
He said disaster response would improve and committed $110bn to rebuilding New Orleans and other affected areas.
Tuesday marks the first anniversary of one of the most costly natural disasters in American history.
The storm devastated an 80-mile (128km) stretch of coast and flooded the majority of New Orleans.
Fewer than 200,000 of the original half-million inhabitants have returned to their ruined homes.
The president said Americans responded with "heroism and compassion" during the crisis but acknowledged that the response of the emergency system had failed.
After Katrina, the authorities were criticised for failing to provide people without adequate means of escape. It meant many of those left behind were the poor and elderly.
Flooding left 80% of the city under water
And the Superdome stadium and Morial Convention Center in New Orleans turned into scenes of misery and desperation when they were packed with thousands of people who had failed to get away before the storm struck.
"Unfortunately, Katrina also revealed that federal, state and local governments were unprepared to respond to such an extraordinary disaster," said Mr Bush.
"And the floodwater exposed a deep-seated poverty that has cut people off from the opportunities of our country.
"The federal government will learn the lessons of Katrina." He said the government would "do what it takes to help our brothers and sisters build a new Gulf Coast where every citizen feels part of the great promise of America".
Mr Bush said he would be visiting Mississippi and New Orleans next week and review progress.
"This work will require the sustained commitment of our government, the generosity and compassion of the American people, and the talent and vision of people determined to restore their homes, neighbourhoods and cities," he said.
Meanwhile, Louisiana's Democratic senator, Mary Landrieu, has delivered a radio address in which she criticised the government's ability to cope with disasters such like Katrina.
"Countless neighbourhoods appear as if the hurricanes were just yesterday, and they serve as harsh reminders of how our nation was so unprepared," Ms Landrieu said.
"Unfortunately, our nation in many ways remains unprepared for major disasters, whether they be hurricanes, earthquakes, or terrorist attacks."
She said that the Federal Emergency Management Agency, which was accused of bungling the response to Katrina, "is but a shell of what it once was only six years ago: stripped of authority and denied resources, it is often unresponsive, inept and badly managed".