The foreign ministers of Egypt and Israel, with the United States acting as host, resumed face-to-face talks yesterday after a delay of six months. There was no sign, however, of early progress toward narrowing the wide gap between them.

Egyptian spokesman Hamdi Nada, speaking to reporters midway through 5 1/2 hours of meetings in a heavily guarded medieval castle, called the Israeli proposals "unacceptable" and said his delegation is "still waiting for more positive response from the Israelis to our initiative and our proposals."

Israeli spokesman Naftali Lavie said the Egyptian proposals are unacceptable to his country but he reported on the meeting in more positive terms and expressed hope for some movement toward agreements.

According to a U.S. spokesman, the meeting was opened with a brief statement by Secretary of State Cyrus Vance with the rest of the time devoted to discussion between Egyptian Foreign Minister Mohammed Kamel and Israeli Foreign Minister Moshe Davan and their teams of advisers.

U.S. officials, who said in advance that the castle talks are aimed at re-starting and then accelerating the stalled Egyptian-Israeli negotiations, have made plans to send special ambassador Alfred L. Atherton to the Middle East later this week to arrange follow-up talks.

The Egyptian spokesman said, however, that Cairo has not decided whether to resume full-scale negotiations with Israel, and he told reporters after the initial session that "nothing happened to enable us to say there will be further talks after the current meetings."

Egypt's official Middle East News Agency quoted President Anwar Sadat as saying late yesterday that it would be useless to hold further talks with Israel "unless there is a response (to Egypt's proposals) or a new element that can be a basis for discussions." Sadat spoke in Khartoum, Sudan where he was attending a meeting of the Organization of African Unity.

Accordng to briefings for more than 100 reporters gathered at the Great Danes Hotel, down the road from the historic Leeds Castle, no new ideas were put forth by either side in the initial stages of the talks.

Vance began sessions in positive fashion by listing points of agreement between the peace plans of the two sides. These are acceptance of five-year transitional period for the Israeli-occupied West Bank and Gaza Strip, a form of self-government for the areas, the need for security arrangements to protect Israel and the objective of normal relations between Egypt and Israel.

Vance did not dwell on the fundamental and central disagreement: whether or not Israel will agree to withdraw under any conditions and to any extent from the areas which it occupied in the 1967 war.

The setting, around a small table in the seminar room of Henry VIII's "Gloriette," which was added to the ancient castle as a royal apartment in the 1500s, was somewhat more formal than the no-table, conversational-style proposed by the American planners. There was no explanation for the change.

The three delegations ate luncheon and dinner together at a baronial oak table. They had no company other than each other, because the castle was sealed off by security men and police. Helicopters flew back and forth over the castlegrounds and police cars ringed the estate outside the castle moat.

The unusual security precautions, which were ordered after Britain received intelligence reports of a possible attack against the meeting by a Palestinian extremist group, were called "far overdone" by Dayan, an illustrious soldier in his earlier days.

He said it was "absolutely unacceptable to me" that the meeting was moved to the remote castle for security reasons from its planned site in a downtown London hotel. As if to show her lack of concern about the potential danger, Dayan's wife left the castle yesterday afternoon to go shopping.

The foreign ministers are expected to give a fuller report on the nature and results of their discussions when they emerge from the two days of meetings and seclusion this afternoon.