The chairmen of eight D.C. City Council committees have recommended increasing Mayor Marion Barry's proposed 1984 budget by $25 million, but without detailing a program to pay for it.

The chairmen's proposals, submitted to council Chairman David A. Clarke this weekend under a new council budget process, include a recommendation to reject Barry's plan to charge electric consumers for the cost of city streetlighting. The mayor had estimated that plan would save the city $12 million.

The chairmen also suggested restoring $4.6 million in General Public Assistance (GPA) funds, $1.7 million in aid to the mentally handicapped and full funding for the city's subsidized school transit fares, as well as adding $15 million to Barry's proposed public school budget.

Under a budget process that is being used for the first time this year, Clarke will take the chairmen's recommendations and prepare a series of proposed budget changes that will form the basis of the council's consideration of Barry's budget.

Clarke said that before he submits his proposals, he will try to reconcile the gap between spending and revenues in the chairmen's recommendations, which call for a total spending increase of $38.7 million over the mayor's budget, but propose only $13.6 million in additional cuts.

"I am left with a difficult task indeed," said Clarke.

He said he may recommend that the council support Barry's streetlighting plan. Clarke also is expected to recommend an increase in public school funding, but less than the amount urged by Hilda Mason (Statehood--At Large), chairman of the education committee.

He is expected to suggest the city will spend about $6 million less than it has budgeted for fuel and heating oil because of declining prices.

In addition, Clarke said, the city could save about $3.3 million by reducing the amount of interest it plans to pay on proposed loans, and he suggested eliminating $2 million scheduled for "contractual services" in the Office of Financial Management.

Meanwhile, Barry has warned the council in a letter that it has a "legal responsibility" to return a balanced budget. He said he would fight efforts to raise more taxes to pay for additional spending.

"I know that . . . most of the members of the council agree that we cannot spend what we do not have," Barry wrote.

Barry said in his letter that President Reagan's proposed freeze on federal workers' pay would cost the city about $19 million in lost sales and income taxes. Barry has said previously said that the president's recommended changes in other taxes and his proposals to increase the District share of costs to operate St. Elizabeths Hospital would cost the city about $50 million if approved by Congress.

"I am opposed to any more than $14.4 million in sales, income or miscellaneous tax increaes in FY 1984," he continued. "Therefore, gaps resulting from failure to pass my proposed legislation would have to be closed primarily through expenditure reduction."

He said his streetlighting proposal and cuts in GPA, other emergency assistance and school transit subsidies would save $20 to $22 million in fiscal 1984, which begins Oct. 1.

Mason and Jerry A. Moore Jr. (R-At Large), chairman of the committee on transportation and environmental affairs, both suggested that the city could raise income taxes to cover their proposals if other funds could not be found.

Moore rejected Barry's streetlighting proposals and school transit subsidy cuts while recommending an extra $1.8 million in the Metro operating budget. Mason has proposed increasing Barry's proposed public school budget by $15 million, to $333.4 million.

The $4.6 million increase in General Public Assistance, which provides aid to temporarily disabled and unemployed workers, would virtually restore that program to full funding. Human Services committee chairman Polly Shackleton (D-Ward 3) also proposed adding $1.7 million to the mayor's proposed spending for aid to mentally retarded persons.

Shackleton recommended a $3.7 million cut in funds for Forest Haven, the city's home for mentally retarded persons, to encourage deinstitutionalization, according to a Shackleton aide.

In addition to the recommendations made by the committee chairmen, Clarke said various council members have informally proposed other possible spending program increases totaling $6.2 million, including $1.3 million for the city's drug addiction program and $1.2 million for job training.

Council members also have informally proposed other possible cuts totaling about $9.5 million, Clarke said. The largest of these would be an $8.2 million savings by eliminating "in-grade" pay raises for city employes. There was little indication of support for this move on the council, and labor leaders said they would fight any such attempt.