Senior adminstration officials, speculating that opinion within Iran over the hostage issue is still sharply divided, yesterday repeated their warnings against "undue optimism" that the 11-month crisis will end soon.

Among those publicly cautioning the American public as the Iranian parliament ended its first day of debate on the hostage issue without agreement were Vice President Mondale and Robert S. Strauss, chairman of President Carter's reelection campaign. Their view was echoed by United Nations Secretary General Kurt Waldheim, who said while there was "some hope" the hostages would be released soon, it is likely to be several more days or even weeks before the answer becomes clear.

In private, U.S. officials scanning the reports from Tehran, said they simply did not have enough information about yesterday's closed-door meeting of the Majlis, or parliament, to draw any conclusions about how long the hostage debate is likely to last or what the outcome will be.

The apparently inconclusive nature of yesterday's meeting led officials to surmise that the hostage issue is still sharply divisive in Iran, and they agreed with Waldheim that it probably will be some time before the picture of where events are heading becomes clear.

"We are taking it one day at a time, and right now no one knows how many days the process is likely to drag on," one official said.

Mondale, interviewed in Los Angeles on "Face the Nation" (CBS, WDVM), insisted that the adminstration had no direct information about what the parliament's commission on the hostages had reported to the full body. The vice president said that just before his TV interview he had talked by phone with Carter and Deputy Secretary of State Warren M. Christopher and added: "We have nothing on which to base any undue optimism."

Mondale also repeated past adminstration denials that the United States is working out some kind of secret deal with the Iranians to secure the hostages' release. In this connection, he stressed that Carter's promises last week to lift restrictions on commercial trade with Iran and to release billions of dollars of frozen Iranian assets would simply be undoing actions originally taken to prod Iran into freeing the captives.

Asked whether unfreezing the assets would permit immediate shipment to Iran of large quantities of military spare parts being held in this country, Mondale said, "We have not had to, nor should we at this point in my opinion, face up to the question of spare parts." That question, he added, should be left to future U.S.-Iranian negotiations, and he insisted, "We do not have such negotiations under way."

The vice president also said he had "no knowledge" of the accuracy of a report by syndicated columnists Rowland Evans and Robert Novak that Israel has been supplying spare parts for the Iranian air force with U.S. approval. "Our position has been to discourage all nations from supplying arms to Iran until our hostages are returned," Mondale said.

The State Department, responding to the Evans and Novak reports, denied yesterday that the United States had given Israel or any other country permission to transfer American-made weapons or spare parts to Iran. The department added it had no information that any such secret resupply effort had been made.

Waldheim, interviewed on "Issues and Answers" (ABC, WJLA), said he is aptimistic, based on his recent talks at the United Nations with Iranian Prime Minister Mohammed Ali Rajai, about Iran's desire to end the long impasse over the hostages, because it wants to end its isolation within the international community and gain support for its position in the current Iran-Iraq war.

But, he added, "we have to be careful and cautious about the exact timing" and warned against expectations of an imminent break in the situation.

"If it were done, then we would need some sort of mechanism to deal with it or at least some formal information that it will happen, and this has not been forthcoming yet," Waldheim said.

Referring to reports that Iran might opt to release only some of its captives, Waldheim warned that the crisis can be resolved only if all the hostages are freed at the same time. "The American authorities have made this crystal clear," he said.

In reference to the recurring rumors of a spare-parts-for-hostages deal, the secretary general said "nothing could be more dangerous" than to attempt to link the two issues. He added:

"That would create a very negative attitude in Iran because they have made clear that the two aspects have nothing to do with each other. Rajai has said the parliament will make its decision independent of any dealings or bargaining . . . that whatever is done will be done without relation to other matters, whether it's the war, military equipment or whatever."

Waldheim said Iran's conditions for release, as outlined to him by Rajai, were the same ones stated publicly last month by Iran's principal leader, Ayatollah Ruhollah Khomeini. These are unfreezing the Iranian assets, dropping U.S. financial claims against Iran, returning the wealth of the late shah Mohammad Reza Pahlavi and promising not to intervene in Iran's internal affairs.

"If there are no additional conditions put forward by the Majlis, I hope this can be settled," Waldheim said. Asked if the Iranians understood the U.S. position that the question of the shah's wealth can be settled only through court action, Waldheim replied that he did not think an agreement would be blocked by this position.

Strauss, appearing on "Meet the Press" (NBC, WRC), denied that Carter was trying to manipulate hopes of a hostage release to win the presidential election. To the contrary, Strauss said, the situation had put the president in a trap.

"It's hell if he does and hell if he doesn't talk about it. . . . The president has tried very hard to see that hopes aren't built up too high. He has admonished the press constantly not to hype the issue because we have been disappointed before."

Strauss also took issue with speculation that Iran might release the hostages before the Nov. 4 election because Khomeini fears victory by Republican Ronald Reagan. The truth, Strauss insisted, is that Khomeini "despises the president" and probably wants to make things as difficult for him as possible.

Mondale, in his television interview, said preparations were being made at the U.S. Air Force hospital in Wiesbaden, West Germany, for possible reception of the hostages. He described these preparations as "prudent, necessary steps," but added that they should not be interpreted as meaning the administration expects an imminent release of the hostages.

A Harvard University psychiatrist, Shervert H. Frazier Jr., said yesterday that two physicians have been put "on call" by the government. Frazier said he did not know whether these moves were related to the hostage situation, but added that at five earlier points in the crisis psychiatrists have been placed "on call" in the event of a release.