In a memo from a key aide in June 1986, Secretary of State George P. Shultz was warned that possibly illegal U.S. arms deals with Iran to free U.S. hostages in Lebanon were still secretly under way and "will have disastrous consequences for foreign policy," according to current and former administration officials.

The memo, which is in the hands of the House and Senate Iran-contra committees before which Shultz appears at 9 this morning, was written June 2, 1986, by Ambassador Robert M. Oakley, then director of the department's office of counterterrorism. It signaled Shultz that a White House-approved operation that State Department specialists believed was laid to rest the previous December had "reared its ugly head again."

According to a former colleague of Oakley, Shultz never responded to the memo or gave any indication that he took action to try to halt the secret program, which he had initially opposed but later told his staff he was powerless to stop because President Reagan wanted to pursue it.

The memo is part of a collection of documents and testimony that will form the basis for questioning of Shultz today and tomorrow by the Iran-contra panels.

Committee sources expect a major issue in the questioning to be whether Shultz, as Reagan's chief foreign policy adviser, failed to take vigorous action to monitor and oppose a major, high-risk international initiative that undercut the administration's strong position against dealing with terrorists. During the secret 1986 U.S. arms sales, they note, Shultz was promoting a worldwide ban on arms to Iran.

Some Republican members have indicated by their previous questioning of other witnesses that they plan to confront Shultz on the issue of his loyalty to the president after the Iran initiatives were exposed and Shultz publicly revealed that he had initially opposed them.

Shultz is also the major administration defender of Assistant Secretary of State Elliott Abrams, whose testimony about misleading Congress, and his support for the Nicaraguan contras while U.S. military aid was cut off, annoyed many committee members.

Congressional investigators have gathered testimony and documents, including the June 1986 memo, that shed new light on what Shultz knew and did about the Iran initiative.

One set of documents shows that Shultz and Oakley became involved in helping to facilitate an Israeli shipment of U.S.-made Hawk antiaircraft missiles to Iran in November 1985. At that time, according to an Oakley affidavit that has been released by the select committees, Oakley authorized then-White House aide Oliver L. North to contact the U.S. Embassy in Portugal to get help.

According to State Department counsel Abraham D. Sofaer, Shultz told Attorney General Edwin Meese III last Nov. 22 that he believed the Hawks were to be sent only if U.S. hostages were released and that he did not learn until early 1986 that 18 of the missiles had, in fact, been delivered.

Because the shipments ran counter to U.S. policy against selling arms to Iran and dealing with terrorists, Shultz and his aides pressed for a meeting that took place at the White House on Dec. 7, 1985, which gave Shultz and Secretary of Defense Caspar W. Weinberger an opportunity to voice their strong opposition to the Iran initiative directly to the president. Shultz later told those few State Department aides who were aware of the initiative that he thought it had been ended.

In contrast to that, Shultz told the Tower review board that he understood in December 1985 that Reagan wanted to keep the program going.

Shultz attended the two high-level meetings on Jan. 7 and Jan. 16, 1986, that set in motion, with the president's approval, the program that culminated in five shipments of American TOW antitank missiles and Hawk spare parts to Iran between February and October, and the release of two U.S. hostages.

At the Jan. 16 meeting, at which senior officials discussed the presidential "intelligence finding" authorizing the initiative, Shultz left early. According to former national security adviser John M. Poindexter, Shultz said, "Well, John, you know my view on this. I don't think we ought to go ahead with it."

Poindexter said Shultz did not participate in the discussions that followed, but indicated at a later date "that he didn't particularly want to know the details. {Shultz} said, 'Just, in effect, tell me what I need to know.' "

Last November and December, Shultz contended that he generally had been misled and kept uninformed about the controversial Iran policy. He told the attorney general, the House Foreign Affairs Committee and the Senate Select Committee on Intelligence that he only learned on Nov. 19, 1986, that Reagan had signed an intelligence finding authorizing the initiatives the previous January.

Shultz told the Tower board that when Poindexter read the intelligence finding at a meeting that day, "I said, 'That's the first I heard of that.' Cap {Weinberger}, who was sitting across the room from me, said, 'I have never heard of it either.' "

Weinberger attended the Jan. 16 White House meeting where the finding was discussed. According to testimony before the Iran-contra committees, Weinberger said he wanted his Defense Department lawyers to review the intelligence finding before giving final approval. He gave it the next day.

Poindexter testified that Shultz approved the "terms of reference," or guidelines, for the discussions that former national security adviser Robert C. McFarlane was to hold with high-ranking Iranian officials. These discussions took place in Tehran in late May 1986, and were accompanied by another U.S. arms shipment intended to bring about the release of American hostages.

Shultz has maintained that he did not know about the Tehran trip or that arms shipment.

Poindexter also testified, and documents indicate, that Shultz was also "aware" that White House-directed efforts were under way last September to establish a "second channel" of communications with the Tehran government.

"I can recall trying to get in touch with him {Shultz} several times during the month of October to discuss with him progress," Poindexter testified Tuesday. "Unfortunately . . . our schedules just didn't permit an adequate number of meetings."

In the first few days after the operation was exposed last November, Shultz sent a cable to Poindexter suggesting that the White House "go public" on the initiative but attempt to portray it as "a special one-time operation based on humanitarian grounds . . , " according to the report of the Senate intelligence committee.

Meanwhile, State Department officials let it be known that Shultz had opposed the initiative from the beginning, and, at a Nov. 16 interview with CBS television's "Face the Nation," Shultz contradicted Reagan's statement three days earlier that Iran had suspended terrorist acts while it was receiving U.S. arms. Shultz maintained that Iran "has and continues to pursue a policy of terrorism."

On Nov. 20, Shultz met privately with Reagan at the White House.

State Department sources have said that Shultz threatened to quit unless untrue accounts of the U.S. role in the November 1985 Israeli-Iran arms transfer were rectified before being given to Congress. White House sources, on the other hand, have said that Reagan summoned Shultz to tell him to support the administration on the issue or resign.