NEW ORLEANS – As federal and local officials argued about when residents should be permitted to return to this evacuated city, hundreds of people have ignored orders to keep out and found their way past scattered armed checkpoints to reoccupy their homes.

Dozens of residents could be seen walking dogs, raking leaves or repairing homes this weekend in those neighborhoods least affected by Hurricane Katrina’s devastation.

“People call and ask me, ‘How did you get in there?’ and I say ‘I drove!’” said Linda Brett, 53, a real estate agent and a resident of Algiers Point who was outside a friend’s house Sunday afternoon.

The outlook was much bleaker in sections such as New Orleans East and the Lower 9th Ward that suffered heavy flooding. Many streets were still covered in mud and debris, and several were impassable. Some were blocked by fallen trees or by houses that had floated off their foundations. Police checkpoints also were stricter.

FEMA’s urban search-and-rescue teams continued to search these areas and turned up several corpses – and one survivor Sunday.

An Oregon National Guardsman indicated he’d heard someone inside one home. The Guardsman had been leaving food for the dog at the home, but Sunday he’d heard a voice. After breaking inside, rescuers found a disoriented 39-year-old man, identified as Reyne Johnson, and his dog.

“He was living in a dark, small wet efficiency (apartment),” said Louie Fernandez, a FEMA spokesman. “He seemed unaware of his surroundings.”

The unofficial arrival of people to this city takes place as Mayor Ray Nagin and Coast Guard Vice Adm. Thad Allen, head of the federal relief effort, differ starkly over the state of health and security in the city.

Nagin has set a schedule for more than 180,000 people to return to various city neighborhoods in the coming weeks, beginning today with the section known as Algiers, across the Mississippi River from the downtown. Over the next week and a half, the Garden District and the French Quarter, the city’s historic heart, are due to open to residents and businesses.

But Allen said New Orleans is not safe and said he will strongly urge Nagin to reconsider that schedule, citing the possibility of additional flooding, security issues and fears of disease.

New Orleans’ health care facilities have been shattered to an extent unmatched in U.S. history, and its hospital system faces grave challenges as residents begin returning, warned the vice president of the national hospital accreditation organization Sunday.

The official, Joe Cappiello, said several hospitals were probably damaged beyond repair by Hurricane Katrina, while some may try to rush back into business before conditions are safe. Although the city has more than a dozen hospitals, none has resumed normal operations.

In Algiers on Sunday morning, worshippers gathered for Mass at the Holy Name of Mary Catholic Church. At the river’s edge, dozens turned up for groceries distributed by troops. Residents there say they have power, water and even cable TV service.

But even in those parts of New Orleans where businesses have been invited to return, many are still shuttered.