The senators who oversee the District of Columbia budget are expected to meet today and recommend that the Senate reject a ban on publicly financed abortions in the city that was voted Tuesday by the House of Representatives.

Sen. Patrick J. Leahy (D-Vt.), chairman of the House D.C. appropriations subcommittee, and Sen. Charles McC. Mathias Jr. (R-Md), its ranking minority member, plan to act informally in hope of speeding Senate passage of the budget, a subcommittee aide said.

Leahy and Mathias will also tentatively decide at their meeting on the size and shape of the city budget and clear it with other members before recommending it to the full Appropriations Committee. Their timetable anticipates Senate action before the August recess.

The two lawmakers reached that plan, the aide said, before the House adopted the abortion ban proposed by Rep. Robert K. Dornan (R-Calif.) that put the District into the crossfire of the emotional nationwide debate over abortions.

Both senators have voted in the past to provide abortion funds under the federal Medicaid program. People close to them said yesterday they expect both senators to vote to permit the city to continue using its own tax funds to provide abortions for poor women.

Leahy, a Catholic, has taken that position despite personal opposition to abortions. As a result, he is among six senators targeted by the Life Amendment Political Action Committee, a Washington-based pro-life group, for defeat when he stands for reelection next year.

Paul Brown, director of the political action group, said he expects to take advantage of the fact that Leahy for the first time has political control over a bill that explicitly deals with the abortion issue.

"Although we did not design the Dornan amendment, we are glad to see it in his (Leahy's) committee," Brown said. "We will be happy to inform everyone up there in Vermont...."

On the other side, the National Abortion Rights Action League will do what it can to get word of Leahy's expected support to its Vermont members and affiliates, according to Kay Harrold, deputy deirector.

Leahy could not be reached for comment.

Before the Senate has a chance to $&(WORD ILLEGIBLE vote on the District measure, it probably already will have acted on another bill that - in its present form - bans the use of Medicaid funds for abortions. The measure will provide funds to operate the U.S. departments of Labor and Health, Education and Welfare during the 1980 fiscal year, which begins Oct. 1.

As approved for Senate action by the Appropriations Committee, the Labor-HEW bill contains the abortion ban written into it by the House. A Senate staff member said the committee decided to let the full Senate membership decide the issue.

Dornan's provision in the D.C. bill is similar but not identical to the one in the Labor-HEW bill. It would prohibit the city from spending either federal or D.C. funds to finance abortions.

Albert P. Russo, director of the D.C. Human Resources Department, which provides funds for abortions under a program for the medically indigent, said he was "stunned that the House of Representatives is so far away from accepting the reality of home rule for the District of Columbia."

Russo, also a Catholic who said he is torn by the issue, said the ban voted by the House could prove to be far more financially costly than what the city spends on abortions.

In the 12-month period that ended last July 31, Russo said the city paid $1.9 million for 5,692 abortions - an average of $356 each. The average $1,200, and the cost of keeping a child cost of a city-financed live birth is on welfare for one year is $720, Russo said. Moreover, an increase in births could lead to demands for more city-financed foster care, he said.

One senior Republican in the House, who voted against the abortion ban, said he agreed that the prohibition ran contrary to the city's hard-won home rule. Many on the other side of the issue were movitated, he said, by their ability to cast a vote on an emotional issue without affecting any of their own constituents.

Rep. Millicent Fenwick (R-N.J.), an opponent of the ban, said it discriminates by keeping poor women from having a surgical procedure that wealthier women can buy legally with their own money.

"This whole line-by-line business (in congressional action on the D.C. budget) has got to end," she said.

On the other side, Rep. Robert E. Bauman (R-Md.) said he did not see any home rule issue. "I don't feel at all uncomfortable (as a national lawmaker) if I can save a life by preventing abortions - the District of Columbia is still part of the United States," he said.

The D.C. budget, as passed Tuesday by the House, provides for an operating budget of nearly $1.4 billion to be supported in part by a federal payment of $191.5 million. City officials have asked for increases in both, contending the House version cuts deeply into social programs.