The District, the first of the major local jurisdictions to feel the pinch of a regional economic slowdown, is expected to finish the fiscal year Sept. 30 with a $93 million budget shortfall, its largest deficit in a decade, Mayor Marion Barry announced yesterday.

Unless the next mayor and D.C. Council agree to a combination of budget cuts and tax increases and Congress approves an increased federal payment, the deficit will probably more than double in the coming year, Barry said.

Barry told reporters that his staff is preparing a revised budget for the fiscal year that begins Oct. 1. That document is likely to include at least $100 million in across-the-board spending cuts and a revived proposal to raise taxes, possibly on professional services, according to the mayor and his advisers.

Adding to the city's financial woes, the Office of Management and Budget notified the city last month that the $447 million federal payment will be reduced by $161 million should the White House and Congress fail to reach an accord on the federal budget this fall.

Under such a scenario, mandated by the Gramm-Rudman-Hollings budget act but considered relatively unlikely, the city would face an overall budget deficit of $364 million in fiscal 1991, or about 10 percent of the overall budget, according to the mayor.

"The District is in a financial crisis as never before," Barry said during a news conference at the District Building.

Barry stressed that the District is not unique in its financial predicament.

He attributed the problem to a regionwide drop in projected tax revenue, and not to government overspending, as some of his political rivals have asserted.

Virginia officials announced last month that they face a $1.4 billion revenue shortfall over two years, and Gov. L. Douglas Wilder has ordered cuts in education and other parts of the state budget.

Maryland announced a shortfall of $150 million, and Gov. William Donald Schaefer has instituted a hiring freeze.

Barry, who will step down as mayor in January and who is a candidate for an at-large D.C. Council seat, called the news conference a week before the Sept. 11 primary. He used the session to attack the five Democrats seeking his office for not "realistically" offering solutions to the District's financial squeeze.

Each of the five primary contenders has indicated an opposition to raising taxes.

Three of the candidates, Charlene Drew Jarvis, Walter E. Fauntroy and Sharon Pratt Dixon, have ruled out a tax increase.

John Ray said he would not raise income or property taxes, but would not flatly rule out other types of taxes. David A. Clarke said he would consider tax increases only as a last resort.

But Barry said none of the candidates has identified sufficient cuts in the budget -- particularly the human service, public safety and educational programs that constitute the majority of city costs -- to close the projected deficit without a tax increase.

"If you don't cut it out of the budget, you can only make it up in revenue increases," Barry said, "I don't think that a no-tax-increase {policy} by itself is realistic."

Barry also criticized the view expressed by some candidates that the budget can be balanced by steep reductions in the District's 48,000-member work force, which most of the candidates have described as bloated and inefficient.

Although he mentioned no candidates by name, he appeared to single out Dixon, a lawyer and former utility company executive, who has called for the elimination of 2,000 middle- and upper-level management jobs.

"Those who would have you believe we can eliminate thousands of managers without affecting service delivery are misleading the public," Barry said.

Barry said it is uncertain that large numbers of jobs could be immediately eliminated under the city's personnel rules.

Even if they could be eliminated, he said, the resulting savings would amount to only $20 million to $25 million annually -- not nearly enough to balance the budget, he said.

Dixon has said her job elimination plan would save $50 million to $100 million and give the city the credibility it needs to obtain an increased payment from the federal government.

The mayor said the city's primary spending problems are in areas beyond the city's control, such as the prison system and human service programs such as Medicaid.

He said the administration has consistently proposed ideas to expand revenue, but that the ideas were rejected by the D.C. Council.

He said the city also has been hamstrung by the federal government's refusal to raise its annual federal payment to the District, which it gives in lieu of property taxes.

Candidates' assertions that he has mismanaged the city's finances are not only wrong but irrelevant, said Barry.

"They can pass it off on mismanagement. They can say the Barry administration was neglectful, which is not true," the mayor said.

"But at some point next year, the D.C. government, regardless of what you're trying to do, is going to run out of money."

The projected budget deficit would be the largest since 1980, when the District posted a $105 million budget deficit.

Since then, the city has balanced its budget every year except 1988, when it ended the fiscal year with a $14 million revenue shortfall.