Traffic comes to stop on the Interstate 10 freeway over Lake Pontchartain between New Orleans and Slidell, La., on Wednesday as residents of New Orleans return home after Hurricane Gustav swept through the city. (Kevork Djansezian/Associated Press)Residents of New Orleans are driving back into the city even though the mandatory evacuation order declared in advance of Hurricane Gustav won't be lifted until midnight Wednesday.

Mayor Ray Nagin said no one would be turned away from the city if they tried to come in early, but warned that New Orleans was still in a "very, very vulnerable state."

"I don't want people heading in yet," Nagin said. "But if they jumped the gun, we will let them through."

City workers are busy clearing drains and removing debris in anticipation of midnight Wednesday, after which residents will be officially allowed back to check on their properties, and, if they choose, to stay.

Nagin reluctantly announced the lifting of the evacuation order, despite the fact homes were without electricity or working toilets and a dusk-to-dawn curfew would still be in effect.

The mayor said he had no choice but to begin allowing residents back because neighbouring parishes were reopening Wednesday morning.

"We have this incredible pressure to repopulate and we're trying to respond to that in a responsible manner," he told CBC's Jennifer Westaway, reporting from New Orleans.

Johnny Rosas clears away tree debris from a roadway Tuesday morning in New Orleans, as the city cleans up after Hurricane Gustav. (Brian Lawdermilk/Associated Press)Millions fled the Gulf Coast in fear of Hurricane Gustav, and many were ready to get back home after spending several days in hot, crowded shelters.

Thousands of homes without power

There are still nearly 800,000 homes in Louisiana without power, including about 77,000 in the city of New Orleans.

Officials said the main transmission lines into southern Louisiana were crippled and they had no timetable on when much of the power might be restored.

In addition, hospitals are still understaffed and there is nowhere to buy groceries or gas.

Still, residents who left coastal areas want to return, realizing this was no Katrina, which killed 1,600 people in 2005. Nine deaths have been attributed to Gustav.

Initial inspections showed little damage to the Gulf Coast's extensive oil and gas installations, though resumption of production and refining could still take a few days.

U.S. President George W. Bush is expected to travel to Louisiana on Wednesday to take a look at the damage.

With files from the Associated Press