An $80 million renovation plan to turn some rundown Alexandria apartments that house about 3,000 of the city's poorest residents into housing for young professionals with help from the city was rejected last night by city officials.

The developer, the New Alexandria Associates Group, had sought $55 million in city-backed tax-exempt bond funds. City officials' refusal to go along with that arrangement will not necessarily kill the project if the developer can find conventional private financing. But the officials said the displacement of the residents will at least be postponed.

Stanley Layton, trustee for the current owner of most of the units, and Ira Saul, an attorney for the New Alexandria Associates Group, did not return telephone calls yesterday.

Because the developer failed to disclose by a 5 p.m. deadline yesterday who its principal partners are, Angus Olson, director of the city's Redevelopment and Housing Authority, said he would not issue the tax-free bonds needed to help finance the renovation.

The City Council, which had scheduled a meeting with the developers last night to discuss details of the project, then canceled the meeting.

"We need to know who will be responsible" for the plan that would change the complexion of Arlandria, an area bordering Arlington, Mayor James P. Moran Jr. said.

"We cannot be kept in the dark," the mayor said, about a plan that could constitute "the largest displacement in the city's history" by forcing as many as 3,000 people to move.

Layton, trustee of the estate of the late V. Brooke Layton, which owns most of the 1,057 Arlandria rental units involved in the plan, refused to tell Olson or Moran who was purchasing the properties, the officials said.

"City officials said they believed the properties will still be sold and the apartments renovated, but that it probably will take several months before another plan and financing for it can be arranged.

Thus the failure to get city backing for the project apparently means that hundreds of tenants such as Jacob Hughes, 79, a retired federal security guard, will have a few more months in their Arlandria apartments before a new owner takes over and raises the rent.

"I could make it for a month or two after they raised the rent," said Hughes, who suffers from diabetes and arthritis, "but not longer." He said he would have to move out of the city where he has lived for 35 years.

With a 1.27 percent vacancy rate for rental units and an average rent for a one-bedroom apartment near $530, Alexandria has scant offerings for low-income people outside of Arlandria.

The rent for Hughes' one-bedroom unit in the Dominion Gardens Apartments, which now rents for $400 a month, might have jumped to as much as $572 under the plan rejected last night, although it could have been held at $485.

If the group had received the $55 million in city-approved tax-exempt bonds, which was figured into the plan, the federal government would have required it to keep 20 percent of the one-bedroom units at the $485 lower rate.

Council member Robert L. Calhoun said he had "a lot of problems with the plan," which also asked the city for $6 million worth of road, sewer, landscaping and parking improvements to enhance the development.

Many of the tenants, most of whom are black, Hispanic and Asian, believe it is only a matter of time before they must go somewhere else, said Onka Dekker, a housing counselor.

Dekker blamed the city for "passing the buck" and showing little commitment to keeping low-income residents in the city.

But Moran said the real problem was massive cuts in federal housing assistance, which make it almost impossible for local governments to compete with private developers.

Federal housing funds have been cut by 93 percent since 1977, according to the Washington-based National Low-Income Housing Coalition. Those cutbacks are being felt in Arlandria, and numerous other areas around the country, national housing officials say.