Israel has proposed and Egypt has accepted an Oct. 10 date for convening a Geneva peace conference on the Middle East - but there is no sign of agreement on the knotty question of Palestinian participation.

Israeli Prime Minister Menachem Begin, in a conversation with visiting Sen. Jacob Javits (R.N.Y.) and in a later discussion with reporters, said that Oct. 10 would be the first convenient date for a new Arab-Israeli meeting because Jewish religious holidays precede it.

In response, Egyptian President Anwar Sadat was quoted by the Cairo newspaper Al Ahram as saying: "It is an encouranging sign that Begin announced he will go to Geneva in October. If it happens, we hope the Geneva conference could reconvene on or before October." Sadat consistently has appealed for a new Geneva conference at and early date.

The most important procedural roadblock has been the Arab demand for representation at a conference by the Palestine Liberation Organization (PLO). Israel has strongly opposed PLO participation as a separate delegation or as a part of a combined all-Arab delegation. An Israeli official was quoted yesterday as saying that the Jewish state will not tolerate PLO representatives at the conference.

Begin, when informed of Sadat's comments, said that "any positive reactions on the side of Arab leaders about Israeli suggestions will be received with blessings." He also charged that Sadat has recently given ultimatums and even threats" against Israel

State Department spokesman John Trattner said the United States welcomes both leaders' statements as "positive indications of the desire to get the negotiating started." He noted, however, that discussion of the details leading to a conference must await Begin's meetings with President Carter scheduled to start July 19.

Javits, who is touring the Middle East, said Begin's trip to Washington "is capable of being decisive" in leading to a Geneva conference.

"I believe the President is ready to discuss the specifics of the future of peace, and I hope very much the prime minister (Begin) will be prepared to discuss not just procedures but the specific matters the President has raised," Javits told a news conference in Jerusalem.

Secretary of State Cyrus R. Vance is planning a second trip to the Middle East in late July or early August to follow up on the Carter-Begin meeting and the earlier sessions between the President and Arab leaders. Carter and Vance have said they continue to hope for the convening of a Geneva conference later this year.

There was no immdeiate comment on Begin's statements from Syria and Jordan, which would be parties to any new Geneva conference, or from the PLO.

Trattner denied a United Press International report that the United States is considering establishment of a naval base in Haifa as reassurance to Israel. Tratter said that the report, attributed to White House source, was "pure speculation" and that no such suggestion is under consideration.

Carter, in an effort to explain his Middle East policies to an influential and increasingly critical group, had scheduled a meeting today with 40 leaders of American Jewish organisations. Several Jewish leaders have expressed apprehension about the President's policies on a Middle East settlement and on the possibility of a serious clash with Israel, particularly since Begin and his Likud Party were elected in mid-May.