The Reagan administration yesterday sought an 11th-hour compromise to avert a congressionally ordered shutdown of covert CIA assistance to guerrilla forces operating against the leftist Sandinista government in Nicaragua.

"A compromise is in the works," a high administration official said.

While the precise nature of any compromise was unclear, Rep. C.W. (Bill) Young (R-Fla.), a member of the House Permanent Select Committee on Intelligence, said he had received a telephone call from CIA Director William J. Casey saying that he had proposed a plan that would impose greater restrictions on covert activity in Nicaragua.

Administration sources said the restrictions would be aimed at ensuring that covert activity was limited to interdiction of arms supplies to leftist guerrillas in El Salvador. While this is the supposed purpose of the present covert activity, some administration critics have charged that it is aimed at destabilizing or overthrowing the Sandinista government.

Young said that Casey told him his compromise plan was outlined in a letter last week to Committee Chairman Edward P. Boland (D-Mass.) and J. Kenneth Robinson (R-Va.), the panel's ranking Republican.

Legislation by Boland and Rep. Clement J. Zablocki (D-Wis.) to cut off funds for all covert activity in Nicaragua is scheduled to come up in the committee this morning, but Young said he and Robinson had asked for a delay because of scheduling conflicts.

Young has proposed an amendment that would cut off the funding 45 days after it was determined that Nicaragua was no longer aiding the leftist guerrillas in El Salvador.

When the Senate Intelligence Committee meets at 2 p.m. today it also will have legislation before it to shut down covert aide. The bill, proposed by Sen. David F. Durenberger (R-Minn.), was first considered two weeks ago but was put over because of poor attendance at the session.

Congressional sources said yesterday that there are only "five hard votes" on the Senate committee to cut off covert aid, with eight needed. Two senators, William S. Cohen (R-Maine) and Walter D. Huddleston (D-Ky.), are regarded as undecided.

Efforts to cut off funds for covert activity have divided both parties and provoked lively debate within the administration. The president and his national security advisers have made it known that they prefer no additional restrictions, but they have been told by friendly congressmen that they must make some concessions or face the possibility of a House-voted cutoff on covert assistance.

But the issue also has deeply divided congressional Democrats, risking the fragile unity they appear to have achieved in the House on major domestic legislation.

Last week House Majority Leader James C. Wright Jr. (D-Tex.) delivered a stinging rebuke to the nationally televised response of Sen. Christopher J. Dodd (D-Mass.) to Reagan's speech on Central America before a joint session of Congress.

Wright accused Dodd of "florid rhetoric" and "hyperbole," adding: "I believe in a bipartisan foreign policy. We've got one president."

Some Democrats have privately expressed political concerns that they would be held responsible if the leftists won in El Salvador after Congress cut off funds for covert activity and refused the president the funds he has requested for outright military assistance.

"There are pressures on both sides for a compromise," one administration official said yesterday. "The Democrats don't want to be held responsible for what happens if they cut off the funds. And some of our hard-liners are beginning to realize they're going to have to accept some more restrictions in order to save the package."

The administration is most concerned about winning congressional approval of $60 million in military aid funds that have been bottled up in both houses of Congress. Last week a House Appropriations subcommittee voted to give the administration half of its request.

"Getting the full appropriation is most important to us, but we'd like to keep the covert activity, too, in some form," said an administration official. "It's a tool we'd like to have."