Mayor Marion Barry yesterday dismissed as unrealistic the proposals of the two chief mayoral contenders to erase the District's projected $100 million budget deficit largely by making deep cuts in the 48,000-member city bureaucracy.

Barry said the city work force can be reduced, but only if the public is willing to accept significant cuts in programs and services. Democrat Sharon Pratt Dixon and Republican Maurice T. Turner Jr. have said they would neither reduce services nor raise taxes to eliminate the projected deficit for the fiscal year that began Oct. 1.

The main plank of Dixon's plan is to fire 2,000 non-tenured city managers, while Turner, the former D.C. police chief, has promised to eliminate up to 6,000 jobs through attrition and a hiring freeze.

Barry said yesterday that there are not that many supervisory personnel to fire and that the proposed firings won't work. Asked about the Turner plan, he noted that only 3,000 people left city government last year and many of them were retiring police officers and firefighters. Turner has said that public safety positions would be exempt from his freeze.

"This government can be reduced drastically -- there's no question about it," Barry said. "The only thing I'm saying is that the person who proposes the reductions will have to be prepared for whatever consequences come with it politically and otherwise."

He said some of Turner and Dixon's proposed solutions for the budget crisis "are not real solutions."

Barry and his top financial advisers, meeting with Washington Post reporters and editors, warned that the next mayor faces the prospect of the city running out of cash in the middle of his or her first year in office.

District officials estimate that the city incurred a $93 million budget deficit during the fiscal year that ended Sept. 30, and the deficit is expected to grow this fiscal year.

The mayor and his advisers insisted that the only way to eliminate the deficit is through a combination of deep spending cuts, an increase in the federal payment and an increase in some local taxes.

Barry said he will outline his own proposal to begin addressing the problem when he submits a revised fiscal 1991 budget to the D.C. Council after the Nov. 6 election.

He declined to identify specific recommendations, but he hinted at cuts in some areas, including homeless and foster care programs, both of which have contributed to massive overspending in the Department of Human Services. He also suggested he may look at increasing taxes on public utilities and a surcharge on commercial property taxes.

"You cannot continue to spend at a level more than we're taking in," Barry said. "Unless some corrective action is taken, the next mayor is going to find himself or herself with a negative book balance for the D.C. government."

In an action that could exacerbate the city's financial problems, the Senate Budget Committee yesterday sent to the floor a proposed budget reconciliation plan that includes a provision that would add tens of millions of dollars to the city's annual employee benefit costs.

Currently, the federal government pays the health benefit costs for District workers who retired before 1987, most of whom were hired before the city gained home rule in 1974. But under a proposal approved last week by the Senate Government Affairs Committee as part of the federal budget reduction plan, the costs would now have to be picked up by the D.C. government.

City officials said the cost to the District would be $36 million in 1991, rising to $56 million in 1995.

"It would be a further fiscal burden put on the District of Columbia over an issue we didn't create," said Budget Director Richard C. Siegel.

Barry, who is running for an at-large seat on the D.C. Council, spent part of the interview session deriding proposals by both Dixon and Turner to slash the government bureaucracy -- which many council members have said is bloated and inefficient.

As for Dixon's proposal to fire 2,000 middle and upper-level managers without civil service protections, Barry said Dixon would not be able to find enough managers to cut. He said the government employs only 2,600 managers at the DS-13 level or above.

"There are not 2,000 mid-level managers, who are non-tenured in the D.C. government," he said. "I don't care who you are, you can't find that number."

Barry similarly criticized as unrealistic Turner's proposal to reduce the bureaucracy over a year through attrition and a hiring freeze. Turner has said he could reduce the work force by 6,000 members in a year without any cut in services. However, Barry said that in 1989, fewer than 3,000 D.C. workers left the payroll. Of those who left, 700 were police, fire and corrections officers who had to be replaced immediately, he said.

"Freezing all these positions will not balance the budget," Barry said.

Lon Walls, a spokesman for Turner, said Turner stands by his assertion that a hiring freeze -- coupled with attrition -- could realize substantial savings. He said public safety agencies would be exempt from the freeze.

Florence Tate, a spokeswoman for Dixon, said that Dixon would have no comment about the mayor's remarks. Dixon has expressed confidence throughout the campaign that the bureaucracy could be cut by eliminating term and temporary employees who do not enjoy civil service protections.

Staff writer R.H. Melton contributed to this report.