A frustrated Soviet leadership, angered and worried by the peace initiative of Egyptian President Anwar Sadat, is exercising extreme caution in voicing its views for fear a mistake could harm its carefully nurtured position in the Arab world.

With Sadat's extraordinary one-man display of diplomatic zeal now into its third week, the Soviet leadership has yet to express itself officially on the subject.

Instead, its carefully controlled official press has relied on a conbination of reporting on the widespread criticism of Sadat by other Arab leaders, sly suggestions about motives, standard anti-Israeli bombast, and some innuendo that it is really an American plot.

Informed Western diplomatic sources here who follow the Kremlin's Middle East Policies say that eventually a Soviet position will emerge, but that it may be some time in coming.

"From the insinuations that work into Tass (the official Soviet Press agencey,) you can gather their mood," commented one source. "But what is the official Soviet position? They don't have one. Yet, they feel compelled to comment and eventually they will."

Said another source: "Right now, the Kremlin is letting the Arabs call the tune and that is a position of diplomatic weakness."

Tonight, with the Kremlin awaiting the arrival of Syrian Foreign Minister Abdel Halim Khaddam for consultations on the Egyptian-Israeli moves, the Soviet press again confined itself to reprinting reports from elsewhere in the world.

It used disparaging tones liberally, however, making no secret of Soviet feelings.

"The Cairo newspapers have published a number of articles in which, at long last, they mention again Arab solidarity and unity," Tass said." . . . The papers strive to present matters in such a way as though in his latest speech in the National Assembly Saat had 'upheld' all Arab interests."

Tass quotes the French paper Le Figaro as asserting that Sadat "refuses to support the cause of the Palestine Liberation Organization. Everybody is convinced that Sadat has set his sights on a separate peace with Israel and is accelerating events."

In the same disptach, ostensibly a general roundup of world press comment on the Sadat moves. Tass also declared that "Tel Aviv makes its stand even tougher, tries to get from Egypt further concessions in order to broaden the split in the ranks of Arab countries and above all to strike a blow on the PLO."

In the view of Diplomatic sources.these excerpts define as clearly as is presently available Soviet concerns about the Sadat activities.

Since 1972, when Sadat broke with the Kremlin, expelled Soviet technicians and abrogated a friendship treaty with the U.S.S.R. the Kremlin has concentrated on initiatives with the other Arab states, especially Iraq and Syria.

The net effect, of recent peace initiatives in the Middle East, however has been to push the Soviets to the sidelines, a position they disliked.

Soviet ire at Sadat is heightened, it is seen here, in part because his moves came just a few weeks after the Carter administration, in an intitiative of its own, joined with the Kremlin in calling for a reopening of the Geneva Middle East peace conference.

The U.S. move appeared to insure the Soviets of a role in any final peace settlement.

Moscow is clearly going to listen attentively to what Khaddam has to say, according to observers here, who expect a communique to be issued at the end of the session that will help them shape their own views about Soviet intentions.

"The question is, will the leadership try to get the Syrians to really go after Sadat, or will they try to keep things a little cool and wait to see what develops?" One source asked. "The situation is so complicated that they may continue to hold back a while."

A further complication is the U.S. response to Sadat's call for a Cairo confernce.

"It is one hundred per cent sure the Soviets won't go, no matter what happens," one source said. "But what if the Americans don't go their and keep their response restrained? Then the Kremlin may want to do the same thing, in view of the fact that the Soviets are co-chairman with the U.S. of any Geneva conference."