The need for the Federal Council on the Arts and Humanities, a moribund panel revived by the Carter White House, was sharply questioned yesterday at a House appropriations subcommittee hearing.

Subcommittee chairman Sidney R. Yates (D-III.) wondered whether the council might become a "new layer of bureaucracy" and pressed Arts Endowment Chairman Livingston Biddle to define the panel's functions.

The White House announced two months ago that the federal council, authorized by Congress in 1965 but largely dormant over the years, would be revitalized, and Joan Mondale was named as its honorary chairman.

The scrutiny of the council's functions came up yesterday as the appropriations subcommittee took a lengthy and unusual second-session look at arts endowment budget request for $150 million in the next fiscal year.

That request includes a $50,000 allotment as the endowment's contribution to the newly reactivated federal council. The National Endowment for the Humanities also would kick in $50,000 support.

As Biddle explained the council's role, it would serve as a coordinator, ombudsman and overseer of the cultural programs spread over many government agencies.

As an example of Mondale's "catalytic" role in the arts, Biddle cited her meeting with him and Transportation Secretary Brock Adams on ways to use art to brighten passenger stations and public transportation.

"I'm not showing hostility to the council . . . perhaps there is a function. But I don't see how it can function with the staff of three proposed," Yates observed at one point.

Yates promised to ask the same questions of Joseph D. Duffey, the chairman of the humanities endowment, scheduled to appear before the subcommittee today. Duffey will serve as first head the reactivated council, made up of 14 ex-officio members from agencies with cultural activities.

Yesterday Biddle and his staff came back to the Hill for a second session of questioning by Yates and other subcommittee members.

It was line item questioning the first time that the arts budget has been put under such scrutiny. At the previous session in March, this caught the endowment's staff off guards.

Yates, a congressman who does his homework and salts his questions with humor, said he felt this was a time for a reassessment of the goals of the federal arts endowment.

"We are almost at a watershed," he observed, pointing out that the arts and humanities endowments are over a decade old and have budgets that have grown from $2.5 million the first year to the current $150-million request.

Biddle, presenting his first budget to Congress as successor to Nancy Hanks, pointed out that he has moved on the need for policy and planning with the appointment of David Searles as a deputy chairman with that responsibility.

Yates, who said that he had been visited by a delegation of women artists complaining that galleries often won't show their work, asked Biddle about discrimination against women artists.

Biddle said it was a valid complaint.