Mayor Marion Barry yesterday warned that he may veto the $1.9 billion city operating budget for fiscal 1984 recently approved by the D.C. City Council, saying that the council had unlawfully revised his revenue estimates and has yet to adopt a tax-increase package that is essential to balancing the new budget.

Barry, who has until Monday to act on the budget, told Council Chairman David A. Clarke in a letter that he needs more assurance that the tax package will be adopted.

Clarke and John A. Wilson (D-Ward 2), chairman of the finance committee, called Barry's letter a "public relations stunt" intended to prove that the mayor has not lost control of the budget process. They said that a mayoral veto would be overridden.

In a sharply worded response to Barry's letter, Clarke and Wilson said that Wilson has given the mayor a firm written assurance that the council will approve the $13.5 million tax package.

"We can offer you no more than what you already have from the Council: i.e., the force of law and the strength of the commitments already given you," Clarke and Wilson said.

"This letter was designed as a public relations stunt," Clarke commented. "I don't know what more he can want in the way of commitments from the council."

Clarke said that the mayor may be miffed that the council substantially altered his recommendations in adopting the final version of the budget, and that Barry may be attempting to reassert control over the budget process.

In addition, Barry had appeared visibly angered on Thursday when a council committee rejected his nomination of former council chairman Sterling Tucker to head the Board of Elections and Ethics.

"He's setting up a scene so that he appears to be calling the shots," Clarke said. "It's all imagery."

Last year, Barry threatened to veto the fiscal 1983 budget, but then relented at the last minute.

Wilson said that he had apologized to Barry yesterday morning for the delays in adopting the tax package and had assured the mayor that his committee would meet next Thursday to approve it.

"The time taken to review and revise this package was necessary to insure that the bill presented was both technically and legally sufficient and that committee members would have an adequate opportunity to review the completed package," Wilson said.

In his letter to Clarke, Barry said that he was "in general agreement" with the spending priorities approved by the council for the coming year.

Barry insisted, however, that the council had failed to meet a legal requirement to identify adequately all new revenues necessary to support the budget--an assertion that Clarke and Wilson dispute--and that the council improperly increased his revenue projections.

In balancing the budget, the council assumed that the D.C. Lottery Board will raise about $2.5 million more in revenues next year than Barry's budget experts have projected.

"The responsibility for estimating the revenue that will be generated by any new tax rests solely with the mayor . . . . " Barry contended.

Barry added that he had not received sufficient assurances from the council that his proposed new tax package would be approved. He claimed that the potential $110 million deficit facing the city in the current fiscal year stems in part from the council's failure to adopt the tax package that had accompanied his 1983 budget proposal.

"The fiscal 1983 experience compels me to inform you of my intent to veto the budget in its entirety if our respective roles, responsibilities and obligations in regard to revenue estimation and enactment are not clarified," the mayor said in his letter to Clarke.