NEW ORLEANS - PRESIDENT George W. Bush heads to storm-battered Louisiana on Wednesday to survey damage from Hurricane Gustav as tens of thousands who fled New Orleans prepare to return to a 'dark and hot' city struggling to restore power and maintain basic services.

The visit by Mr Bush, widely criticized for a slow response to Hurricane Katrina, is part of a press by officials to show that they learned the lessons from the 2005 storm that killed 1,500 people and caused $80 billion (S$114.9 billion) in damage.

VIDEO Charting Gustav's path (0:31)

Mr Bush, who skipped the Republican National Convention to oversee the response to Gustav, was expected to arrive in Baton Rouge on Wednesday morning just as residents begin to pour back into the area around New Orleans.

On Tuesday, Mr Bush declared a major disaster across much of Louisiana, where most homes and businesses remain without electricity and hospitals running on backup-power are wary of being overrun by returnees.

The federal disaster declaration clears the way for aid to cover temporary housing for some 2 million who fled before the storm and for low-cost loans to offset uninsured losses.

New Orleans Mayor Ray Nagin said residents could return to on Thursday, lifting a mandatory evacuation order. Other southeast Louisiana parishes nearby New Orleans cleared the way for their residents to return on Wednesday morning.

Mr Nagin, who faced his own criticism for the bungled response to Katrina, cautioned residents they would come home to a city struggling to maintain basic services.

'The message is: We want you to come into the city, check on your property, make sure that you are comfortable and make an intelligent decision on whether you want to stay in this environment or not,' Mr Nagin told reporters.

Hurricane Gustav delivered only a glancing blow to New Orleans and the region's crucial oil and gas infrastructure when it barreled ashore in Louisiana on Monday.

Almost all US energy production in the Gulf of Mexico remained shut but producers said they found little damage to refineries and offshore platforms. Crude oil prices fell to a five-month low.

Gustav also tested a levee system being rebuilt to protect New Orleans from the kind of deluge that followed Katrina, when protections for the city built below sea level collapsed.

Although reinforced New Orleans flood protections will not be finished until 2011, the levees held up under the pounding from Gustav. Water surged over floodwalls and squirted through cracks but the city stayed mainly dry.

But the storm left most Louisiana residents without power, including some 795,000 customers of utility Entergy Corp still without electricity as of Tuesday night. State regulators said it could take up to six weeks to restore power to all customers.

A city left 'dark and hot'
New Orleans officials urged residents to stay away unless they were prepared to live under curfew and rough it without power, gas or access to fully staffed hospitals.

'We all want you home badly, faster possibly than you want to return to a city that is dark and hot,' New Orleans City Council President Jackie Clarkson.

Some 95 per cent of the city's residents fled in advance of Gustav, an unprecedented exodus credited with saving lives.

Louisiana reported just six deaths in the immediate wake of the storm. New Orleans police also said they had arrested only two people for looting during the storm.

That was stark contrast to Katrina's aftermath, when looters roamed the streets and rescue helicopters plucked thousands of people from rooftops and bridges.

The Times Picayune, the city's daily newspaper, said in an editorial on Wednesday that residents were wrong to begin 'second-guessing' the urgent call by officials including Nagin for the large evacuation that peaked during the weekend.

'The low number of fatalities spoke volumes about the effectiveness of of one of the nation's largest and most efficient evacuations,' the newspaper said in an editorial.

Meanwhile, US disaster officials turned their eye to new, dangerous storms churning in the Atlantic.

Tropical Storm Hanna was moving through the Bahamas and threatened the US East Coast from Florida to the Carolinas, and tropical storms Ike and Josephine trekked westward toward the Caribbean.

The Miami-based National Hurricane Center said Hanna was expected to move near the central Bahamas as it begins to strengthen again toward hurricane force. -- REUTERS