New Orleans officially opens its doors at midnight, but Mayor Ray Nagin said no one would be turned away if they chose to return earlier.
He warned that New Orleans was still in a "very, very vulnerable state."
"I don't want people heading in yet. But if they jumped the gun, we will let them through," he said, reported the Associated Press.
After spending days with family members, in motels or in hot, crowded shelters, some of the city's residents expressed anger that it took officials so long to let them return.
"People need to get home, need to get their houses straight and get back to work," said George Johnson, 41, who returned Tuesday night, according to the AP. "They want to keep you out of your own property. That's just not right."
President Bush was scheduled to visit storm-battered areas of Louisiana, including Baton Rouge, on Wednesday. He declared much of the state a major disaster area on Tuesday.
Although the flooding that followed Hurricane Katrina in 2005 was not repeated by Gustav, those returning home encountered another set of problems. Nearly 800,000 homes in Louisiana were without power, including 77,000 in New Orleans alone.
Officials said the main transmission lines into southern Louisiana were damaged and they had no estimate for when electricity would be restored, the AP reported.
When Gustav moved north into Arkansas, whipping the state with strong winds and rain, nearly 100,000 homes and businesses lost power as well.
The death toll for Gustav rose to 16 in the United States, with most occurring in traffic accidents and two in a post-storm tornado. In the Caribbean, 94 people reportedly died.