President Anwar Sadat met yesterday with three top officials to plan a major diplomatic campaign to secure international backing for Egypt's case against Israel now that direct peace negotiations have foundered.

Aside from Egyptian hopes that quiet American diplomacy can revive the talks with Israel, the diplomatic offensive is all that Sadat has put forward since ordering Egypt's delegation home from Jerusalem last Wednesday.

Egypt has used both approaches often in the past, although they have rarely produced major results.

A senior Egyptian official, noting that the peace talks were "frozen" rather than broken off, privately expressed relief that Israeli Prime Minister Menahem Begin declined again yesterday to reconvene the military committee talks in Cairo.

Sadat agreed last week to hold such talks as a gesture to President Carter, who was disturbed at the Egyptian leader's abrupt decision to recall his Jerusalem negotiators.

The Egyptians were worried that a meeting of the Cairo committee, which deals solely with Israeli-occupied Sinai, would only fuel charges by Arab critics that Egypt was seeking a separate peace with the Jewish state.

Assigned to carry the diplomatic campaign to the United States is Sayed Marei, speaker of the People's Assembly. He is expected to see President Carter and congressmen.

Foreign Minister Mohammed Ibrahim Kamel, during visits to Eastern and Western Europe, hopes to confer with British Prime Minister James Callaghan and West German Chancellor Helmut Schmidt.

Vice Foreign Minister Boutros Ghali will travel to African countries.

As has become customary since major American involvement in the Middle East peace process began during the October 1973 war, a prominent American diplomat is expected to shuttle between the adversaries' capitals. This time it is Alfred Atherton Jr., assistant secretary of state for Near Eastern and South Asian affairs.

He was the top American official at the Cairo conference last month and stayed behind after Secretary of State Cyrus Vance left the abortive Jerusalem political talks. Atherton is tentatively expected here tomorrow.

At this point, observers doubt whether meaningful military committee talks could take place until the Americans help the Egyptians and Israelis reach agreement on reconvening the political committee. That, in turn, depends on their ability to work out a declaration of principles, which so far has proved elusive.

Meanwhile, in reply to Begin's earlier remarks - and in anticipation of those he made in the Knesset yesterday - the Egyptian press sought to defend itself against Israeli charges that its use of the word "shylock" was antisemitic.

While the Egyptians contend that the word - denoting a money lender who charges usurious rates - was applied to Israel's bargaining policies, Begin has reacted as though the word was applied to him personally.

Indicative of Egypt's tone of injured innocence was an editorial in the semi-official newspaper Al Ahram. It said that such Israeli complaints did not warrant a reply because "Egypt was the first to break the psychological barrier" and "was and is a living model of tolerance."

Some Egyptians seem genuinely astonished that the Shylock image is offensive to Israelis. But Begin's insistent reiteration of the theme has now made it clear to Egyptians that Israel is making major propaganda points in the West, where Shylock is considered an antisemitic caricature. The Shylock of Shakespeare's "Merchant of Venice" was a Jew and a villain.

Tonight, in talking with Egyptian journalists, the foreign minister urged a calm re-evaluation of the negotiations. In apparent rebuttal to Begin, he said: "We cannot be accused of antisemitism because we are Semites ourselves,"

However, the Egyptians are usually regarded ethnically as a Hamitic people, descendants of Ham. Semitic peoples are descended from Shem whose tribe, the Bible says, grew to include the Hebrews, Assyrians, Phoenicians and inhabitants of the Arabian peninsula.

The minister suggested the Egyptian press had erred "in the last few days" but insisted "nobody in Egypt has antisemitic or anti-Jewish sentiments in his heart."

News services added these Middle East developments:

The Egyptian magazine October reported that Israeli security bugged all rooms of Egyptian officials and journalists attending the Jerusalem political talks. The weekly said the discovery by Egyptian security authorities in the Hilton Hotel in Jerusalem triggered discussions between Egyptian and Israeli security authorities, but it did not elaborate. Israel has denied that it bugged the rooms.

Official sources in Damascus, Syria, said Arab hard-liners opposed to the Egyptian peace initiative will meet at the summit level in Algiers before the end of the month. Several previous attempts by radical Arab states to coordinate their policies foundered on the long-standing hostility between Iraq and Syria. President Houari Boumediene of Algeria has been shuttling around the Middle East to line up the radicals against Egypt, apparently with some success.

In Lebanon, right-wing Christian forces fought a running mortar and artillery duel with Palestinian guerrillas in the south. Authorities reported at least four persons killed.