Egyptian Foreign Minister Mohammed Kamel arrived here today for peace talks with Israeli officials after the Israeli Cabinet, under pressure from the United States, dropped agenda demands that had threatened the negotiations.

Because of the diplomatic maneuvering that was required to resolve the last-minute deadlock -- dealing with the treatment of the Palestinian issue in the agenda -- the opening of the talks, originally set for Monday, has been postponed until Tuesday.

The Egyptian delegation, which had delayed its departure from Cairo pending an acceptable resolution to the dispute, arrived here this evening, several hours later than had been expected.

Secretary of State Cyrus R. Vance, whose postponement last night of his departure from Washington suddenly brought the issue to a head, is expected to arrive here late Monday, 24 hours later than originally planned.

Despite the agenda problems, leaders of the Egyptian and Israeli delegations to the talks expressed optimism and a willingness to work together.

Kamel said, "I am looking forward to trying to achieve tangible and concrete results," adding that, "we are at a crucial crossroads."

Foreign Minister Moshe Dayan, who will head the Israeli delegation, told the Egyptians that Israel "shall listen very carefully and attentively to what you have to say." Dayan added that Israel would be "most forthcoming" in the talks.

Mursi Saad el Din, the spokesman for the Egyptian delegation, told reporters later, "Thanks to American mediation there were some positive developments that enabled the Egyptian delegation to come."

Thus, the crisis that began with Vance's dramatic decision to postpone his departure for Israel until an agenda agreement had been reached now appears to have calmed down.

Vance's action took the Israelis by surprise, however, The Israelis have been saying for days that if an agreement could not be reached prior to the talks, then the first few days of the conference would be devoted to the agenda question.

The American decision to knock heads together and refuse to come until the agenda question could be resolved in advance was a departure from the low-key approach that Vance has exhibited so far. Such American pressure has not been used so publicly since the days of Henry A. Kissinger and the Israelis were unprepared for it.

It was clear to Israel that the Americans did not want to waste Vance's time in Jerusalem on agenda matters and resorted to the tactics of shock diplomacy that appear to have become the norm in the Middle East.

At noon, while the Cabinet was still in session, the Israeli Foreign Office still had no idea whether the Egyptian delegation would arrive today as planned or, indeed, whether there would even be a conference.

Although the Israelis did not make public their new agenda proposals, officials here did not deny that the main sticking point was the "formation of an item for the discussion of the West Bank and Gaza and the Palestinian issue," as State Department spokesman Ken Brown said in Washington.

There has been no complete agreement on the agenda since the Cairo conference opened early last month, because there has never been enough agreement on substance to get an agenda. In the political maneuverings now taking place, both sides have tried to draw up an agenda with wording that would set a course favorable to them in the discussions to follow.

For example, Egypt always wanted an agenda that would draw the negotiations toward a detailed discussion on eventual self-determination for the Palestinians. The Israelis wanted an agenda drawing the discussions toward Prime Minister Menahem Begin's plan for "self-rule" on the West Bank and in Gaza, which basically avoids the self-determination issue.

The settlements issue was also a stumbling block but was not apparently the major point of contention.

The Foreign Ministry announced that contrary to what the United Nations had previously said, Gen. Ensio Silasvuo, who represented the United Nations at the opening of the talks in Cairo would be sitting in on the political committee deliberations here.

Previously, Israel had been told that U.N. Secretary General Kurt Waldheim had not given his permission for Silasvuo to attend the talks. No explanation was given for the change of plans.

Once the agenda issue is settled, Vance's major task here will be to get a joint Israeli-Egyptian declaration of principles -- which was almost achieved when Begin and Sadat met on Christmas Day. The hope is that a suitable declaration of principles might allow the Jordanians to join the talks later.

Nevertheless, the expectation here is that the negotiations will be tough. Sadat says he has given everything that he can give now and it is up to the Israelis to decide whether they want peace or territory. Kamel repeated, upon his arrival here tonight, Sadat's earlier statements that there can be no peace without Israeli withdrawal from occupied territories and no peace without Palestinian self-determination.

But Begin does not accept that Sadat has given everything possible and he is looking for more concessions and compromises from the Egyptians.

The conference is likely to last for weeks, if not months, and will probably go in fits and starts, with the delegations breaking off from time to time to seek instructions.

The same will be true of the military committee talks scheduled to reconvene in Cairo again this week. The war of nerves that surrounds every important negotiation will undoubtedly continue.