The most controversial proposal, reported on Sunday by The New York Times, would have allowed residents to return soon to all sections of the city but within a year would close those neighborhoods that did not achieve a critical mass of residents. A leader of the commission, Joseph C. Canizaro, said Tuesday that members had modified that proposal over the last two days and now believed that no one should be allowed back into the most damaged neighborhoods until June.

City services will probably be more readily available then, Mr. Canizaro said, and the extra time will allow the city to identify who wants to return and set up planning teams for each neighborhood.

"My concern," he said, "is for people who have the money and we let fix up a place and then they find themselves sitting all by themselves without any neighbors around."

By Aug. 20, under the plan, the city should begin the neighborhood reconstruction and should begin acquiring property for public projects like expanding parks. Some low-lying neighborhoods may become parks or marshland if they do not attract enough housing development.

One measure of whether a neighborhood will succeed will be whether it has enough residents to justify a high school and two primary schools.

An essential element, Mr. Canizaro said, is forming the Crescent City Recovery Corporation, through which federal funds would flow. The corporation would have the power to buy and sell property for redevelopment, including the use of eminent domain, and could issue bonds.

Board members of the recovery corporation, to number seven to 15 under the plan, would be appointed by the president, the governor, the mayor and the City Council.

"If we don't get a reconstruction authority in place right away, we won't have a chance with implementation," Mr. Canizaro said.

To create such an agency, however, the city needs to amend its charter, he and others said.