Two days before leaving office, D.C. Mayor Marion Barry announced yesterday that the city's deficit for the 1990 fiscal year will total $114 million, or $21 million more than previously estimated.

Barry blamed the revised figures on a decline in revenue brought on by a slumping regional economy, and not on mismanagement or overspending. Although the Departments of Human Services and Corrections exceeded their budgets during the fiscal year that ended Sept. 30, Barry said, other agencies compensated by coming in under budget.

"All of this is similar to what's going on in Maryland and Virginia," Barry said, referring to revenue shortfalls in the neighboring jurisdictions.

Barry's assessment of the budget came during his final news conference as mayor, a somewhat wistful event in which Barry joked about his tempestuous relationship with the media and about his "grand and glorious 12 years" as the District's chief executive. Barry steps down tomorrow, to be succeeded by Sharon Pratt Dixon.

The official budget figures for fiscal 1990 won't be released until the city audit is completed in February. Meanwhile, Dixon aides are continuing to devise strategies to deal with a projected $300 million deficit for the current fiscal year.

Dixon is planning to make a major announcement about the budget on Thursday, and sources say she is likely to call for about $200 million in spending reductions. Of the total, about $125 million would be achieved by ordering cuts in specific agency budgets, and the remainder would come from canceling scheduled pay increases for city workers.

The Washington Post incorrectly reported Sunday that Dixon's advisers were considering spending cuts totaling $250 million.

Dixon also is expected to ask Congress for a special appropriation of $100 million to close the deficit in 1991.

Among Barry's last official acts was to sign 50 bills recently approved by the D.C. Council, including emergency legislation granting the D.C. banking office additional powers to investigate firms such as the failed Latin Investment Corp., his aides said.

Barry also signed a bill renaming the Southeast-Southwest Freeway after President Dwight D. Eisenhower, eliminating compensation for the board of the University of the District of Columbia and granting a height exemption for the Market Square North residential and commercial development planned for downtown Washington.

Barry still has two bills on his desk without his signature, including legislation granting the D.C. Council authority to review all city contracts in excess of $1 million.

The other bill would limit the administration's ability to procure services without formal contracts, a practice sometimes used by the Department of Human Services because of problems in its procurement division.

Earlier in the day, an aide said Barry was not expected to sign either bill and would instead leave the decision up to Dixon. Barry said he would not reveal his plans, saying he wants to discuss it with Dixon first.

"I'm going to give her what I think the options are and let her decide which one she wants to take," Barry said.

If he defers the matter, Dixon would have until Jan. 8 to veto the measure on council review of contracts worth more than $1 million. Dixon has expressed concerns about the contracting measure and its potential for hindering her reform efforts in D.C. government. Proponents on the council said the measure would give the body a powerful tool for monitoring spending by the executive branch.

Dixon spokeswoman Pam Taylor, citing an interest in maintaining peace with the council in the important early days of the administration, said she doubts Dixon would veto the measure.

"I don't think she would want to risk a council override or risk angering them when there are so many more important issues she needs their support on," Taylor said.