Obama hails New Orleans 'resilience'

Five years after Hurricane Katrina ripped through New Orleans, the city has remembered the catastrophic event with candlelight vigils, parades and a visit from the president.

US President Barack Obama praised the city's resilience and pledged support for rebuilding, as he marked the anniversary on Sunday.

"My administration is going to stand with you, and fight alongside you, until the job is done," Obama told an invitation-only audience at New Orleans' Xavier University.

Obama spoke five years to the day from when Hurricane Katrina roared onshore in Louisiana, tearing through levees and flooding 80 per cent of New Orleans.

He acknowledged that the famed jazz city, where at least 1500 people died in the storm and its aftermath, was still in need of support, but said community efforts had ensured "New Orleans is blossoming once more".

The president said there were still too many vacant lots, trailers serving as classrooms, displaced residents and people out of work.

But he said New Orleanians had shown amazing resilience.

"Because of you," the president declared, "New Orleans is coming back."

Obama acknowledged that the storm, which brought waves of water that overcame levees carrying homes and residents away, "was a natural disaster, but also a man-made catastrophe, a shameful breakdown in government".

But he pledged that the region, struggling with the long-term effects of the tragedy, the economic downturn and, most recently the Gulf of Mexico oil spill, would be able to rely on the administration for support.

He said the rebuilding would bring the city improved schools, health care and housing, making it a better place than it was before Katrina.

"Together, we are helping to make New Orleans a place that stands for what we can do in America - not just for what we can't do," Obama said.

Obama offered a list of accomplishments on Katrina recovery he said his administration had achieved, including helping move residents out of temporary housing, streamlining money for schools and restoration projects, and working to rebuild the poorly maintained levee system that failed the city when Katrina struck.

"New Orleans could have remained a symbol of destruction and decay; of a storm that came and the inadequate response that followed," Obama said on Sunday.

"But it's a symbol of resilience, of community, of the fundamental responsibility we have for each other."

Katrina roared ashore five years ago August 29, killing 1800 people across the Gulf Coast and causing more than $US100 billion ($A110.96 billion) in damage.

The storm plunged New Orleans into chaos, and rescue services were overrun as the disaster reached deep into neighbouring Mississippi and Alabama.

Footage of desperate Americans, waving signs reading "Help Us," horrified people at home and abroad.

Many of New Orleans' flooded neighbourhoods have recovered, and the city has returned to 78 per cent of its pre-storm population.

However, 100,000 New Orleanians remain displaced, and whole neighbourhoods in the city remain abandoned to rot and ruin.

During his speech, Obama also addressed the recent Gulf of Mexico oil spill crisis, triggered when a rig leased by energy company BP exploded off Louisiana's coast in April, unleashing the largest offshore spill in US history. Eleven of the crew were killed.

Obama said his administration would continue to pressure BP to repay individuals and businesses hurt by the spill.

"We are going to stand with you until the oil is cleaned up, the environment is restored, polluters are held accountable, communities are made whole, and this region is back on its feet," Obama said.

The day of commemorations concluded with a memorial service combining commemoration with celebration at the Mahalia Jackson Theatre in the heart of downtown New Orleans.

"We must face the truth that in the fifth year of the 21st century, for four horrific days, there was anarchy on the streets of America," said Mayor Mitch Landrieu.

"The levees broke and our government failed. It's a moment we should never forget and one that we should never repeat."

"America, hear this," Landrieu continued. "The people of New Orleans are still standing, unbowed and unbroken."

Several candlelight vigils were held across the city but it was the president's visit that drew most of the attention.