It took days for authorities to rescue many of the residents stranded in the New Orleans area, where flood waters in some parts rose so high that people went to rooftops for safety. The city was eventually evacuated and rescue personnel conducted door-to-door searches.

The review led by Frances Townsend, homeland security adviser to Bush, follows a congressional report that sharply criticised the US government's disaster response.

"I wasn't satisfied with the federal response," Bush said at a Cabinet meeting. "The report helps us anticipate how to better respond to future disasters."

The 217-page report acknowledged inadequate preparation for the storm and said the current homeland security system "has structural flaws for addressing catastrophic events." But it did not single out anyone for blame.

Senate Democratic leader Harry Reid of Nevada called for an independent commission to investigate government failures in the response to Katrina, which struck on Aug. 29.

"It is, regrettably, an understated and often-times self-congratulatory report written by those who were part of one of the most damaging and disturbing government failures in our history," he said.

The review said better planning, coordination, communication and designation of responsibilities were required, and identified 11 changes needed before June 1, the start of the next hurricane season. Those included establishing an interagency Joint Field Office to manage federal efforts when there are warnings of a potential disaster.

NATIONAL GUARD

The review advocated more disaster-relief training and equipping of the National Guard, who are part-time troops under the command of state governors but can also be mobilised by the Pentagon in times of emergency.

"In truly catastrophic events state and locals may be incapacitated or overwhelmed or even worse," Townsend said.

"It may be that our military is the last and only resort. We need to plan and prepare for the Department of Defense to play a significant supporting role during future catastrophic events," she said.

Townsend said the "bright lines" should be preserved, referring to an 1878 law, The Posse Comitatus Act, which restricts the government from using the military in a law enforcement capacity within the United States. But the president can waive the law in an emergency.

The National Guard can support law enforcement functions in a way active duty military do not, Townsend said. "So you can preserve the bright lines and not seek additional authorities."

A change in law was not required for deploying military forces to help in disasters, she said. "We did not believe the president needed additional authority."

The 600-page National Response Plan needs to be rewritten "so it is workable and it is clear," Townsend said.

The White House will also form the Disaster Response Group, overseen by Townsend, to "cut through the red tape and to referee any needless disputes that arise in the heat of an emergency," she said.

A report by congressional Republicans last week said federal emergency agencies were unprepared for Katrina and quicker White House involvement might have helped.