D.C. Mayor Marion Barry's administration, which has been sharply criticized over proposed social service cuts, is preparing a new $2 million to $3 million assistance program for persons with long-term disabilities.

The program would help people most affected by the mayor's proposal to eliminate the city's $14 million General Public Assistance program for the unemployed and disabled, officials said yesterday. The potential loss of the GPA program has spurred an outcry from community groups and some City Council members, who said the elimination of GPA without any alternative would be unacceptable.

"The feeling I have is that the safety net is being pulled out," Council Chairman David A. Clarke said at a council budget hearing yesterday. "There is a cadre of people for which there are no jobs, and the government has a responsibility to take care of them."

D.C. Social Services Commissioner Audrey Rowe said the long-term disability program would serve about 1,500 people who would lose all benefits and would not be eligible for any other assistance if GPA is eliminated.

GPA, originally designed to provide short-term aid to the temporarily disabled, has developed into a program of last resort for needy persons not covered by other forms of assistance. GPA now provides about 5,500 persons with an average of $189 a month in benefits.

The mayor's fiscal 1984 budget proposed eliminating GPA and transferring about $6 million of the funds to a more modest emergency assistance program, which would provide one-time cash grants to unemployed persons who need to pay some overdue bills.

Some GPA recipients would be encouraged to file for federal disability benefits, but only persons who are totally and permanently disabled are eligible for those.

Council member Polly Shackleton (D-Ward 3), chairman of the Committee on Human Services, presided over yesterday's hearing. She had told city officials earlier that she wanted them to come up with new alternatives for helping the needy, calling the plan in the mayor's budget "simply unacceptable."

She also opposed the proposed elimination of the medical charities program, which provides free care for the poor not covered by any other health program, many of them GPA recipients.

The hearing was conducted before a standing-room-only crowd made up largely of representatives of nonprofit charity organizations who came to protest the cuts in the social services budget.

Catholic Auxiliary Bishop Eugene A. Marino said he felt "a gnawing conviction that this budget is a turning point. I fear we may be starting down . . . a road of indifference and neglect paved with mistaken assumptions, overoptimistic forecasts and budget gimmicks."

Nancy Smith, director of the Child Advocacy Center, urged the council to shift funds from other parts of the budget to retain social service programs.

She pointed in particular to proposed increases of $500,000 in arts and humanities, $2 million for the city's financial management system and $1 million for advisory neighborhood commissions.

Shackleton agreed that doubling the budget for the neighborhood commissions from $1 million to $2 million "is a very poor idea."

Council member H.R. Crawford (Ward 7) asked officials of the Department of Human Services why renovations are continuing at Cedar Knoll when the mayor has proposed closing the facility.

The DHS officials said the renovation plans started several years ago and are just being completed now, and pointed out that children are still housed at the facility.

The department hopes to transfer youths requiring maximum security to the currently underused Children's Receiving Home, but first would have to get permission to do this through the courts and would have to renovate that facility, the officials said.