Congressional opposition to a shipment of nuclear fuel to India is mounting, and critics in House and Senate will seek to block it in a test of strength with President Carter over policy on the spread of nuclear weapons.

The president's stated intent to ship the fuel to India in the face of a unanimous vote against shipment by the Nuclear Regulatory Commission has prompted key Senate and House leaders to voice discontent to the White House and State Department. The Senate Foreign Relations Committee has scheduled hearings on the issue for next month and the Senate Governmental Affairs Committee is considering calling its own hearings.

Sen. John Glenn (D-Ohio), chairman of the subcommittee on nuclear proliferation, advised Secretary of State Edmund S. Muskie yesterday to tell the president to delay approval of the shipment to India until Congress has given the issue a full airing.

"Glenn told Muskie he felt that if the president makes a quick decision to override the NRC he could lose on the issue in the Senate," an aide to Glenn said yesterday. "He told Muskie that he felt the United States would be abandoning its policy on weapons spread if the Indian licenses are approved."

On the House side, Rep. Clement Zablocki (D-Wis.), chairman of the Foreign Affairs Committee, said there is considerable opposition to the Indian shipments in the committee and it could easily be beaten by committee vote.

"Our general feeling is that if we waive the law for India, we lose any leverage we have with out countries on nuclear weapons spread," Zablocki said in an interview. "We could lose our credibility on this one."

Rep. Jonathan Bingham (D-N.Y.), chairman of the House subcommittee on international economic policy, who voted to approve the shipment of nuclear fuel to India two years ago, said yesterday he opposes the new shipments and plans to fight.

"I hope the president doesn't approve this shipment and I hope he doesn't send it up here for approval," Bingham said yesterday. "It would be a grave mistake in this case and I have sent word to the White House that if the president approves it I will file a resolution of disapproval."

Four other House members sent a letter Thursday urging Carter not to overturn the May 16 vote by the NRC. The letter was sent by Edward Markey (D-Mass.), Mickey Edwards (R-Okla.), John Buchanan (R-Alaska) and Thomas Downey (D.-N.Y.). They also circulated a "Dear Colleague" letter to all House members seeking support.

The licenses for India involve two shipments of 19 tons of enriched uranium for the nuclear power station at Tarapur, north of Bombay. Last week the NRC voted disapproval of both shipments on grounds that they violated the two key provisions of the 1978 Nuclear Non-Proliferation Act.

The 1978 law bars shipments of nuclear fuel to countries that have not signed the Non-Proliferation Treaty banning the spread of nuclear weapons and that refuse to open all their nuclear research facilities to inspection.

"I voted for approval the last time on grounds that we needed time to talk to India about these things," Bingham said. "Not only has no progress been made on these two issues, but India has moved a step backward in that Prime Minister (Indira) Gandhi won't even give us the same assurances on nuclear weapons development that Prime Minister (Moraji) Desai did two years ago."

Though he has yet to sign an executive order approving shipments to India, Carter has said he plans to do so to strengthen U.S. ties with India. Carter has told congressional leaders the United States cannot afford to anger India because of unstable situations in Iran and Afghanistan.