White House officials continued yesterday to make preparations for a second Middle East summit conference at Camp David that could begin as early as Thursday.

Adding to the speculation that the summit conference in Maryland's Catoctin Mountains will begin this week, presidential press secretary Jody powell yesterday spoke openly of the possibility that Vice President Mondale will appear in place of President Carter at a $1,000-a-plate Democratic Party fundraising dinner in Los Angeles Friday.

But officials said the key in determining whether there will be a second summit at the presidential retreat rests with the Israeli cabinet, which is to meet today to discuss the issue.

While awaiting that decision, however, U.S. officials continued to make logistical and other arrangements for a repeat of September's dramatic 13-day Camp David summit that produced two "frameworks" -- thus far uncompleted -- for a Middle East peace settlement.

The president, after meeting Sunday at the White House with Egyptian Prime Minister Mustafa Khalil and Israeli Foreign Minister Moshe Dayan, announced that the United States was talking to both governments about raising the peace negotiations to the "head-of-government level."

Egypt would be represented at a second summit by Khalil and Israel by Prime Minister Menachem Begin.

Khalil spent five days at Camp David last week meeting with Dayan and Secretary of State Cyrus R. Vance in an attempt to break the Egyptian-Israeli peace treaty deadlock. The U.S. suggestion of a new summit, which Carter would attend, and comments by U.S. officials strongly suggested that last week's talks resulted in progress toward a separate Egyptian-Israeli peace treaty, the goal of one of the "frameworks" reached in September.

Khalil and Dayan returned to the Middle East yesterday to report to their governments on last week's talks and the prospects for another summit.

Officially, White House aides said it would not be necessary for Egyptian President Anwar Sadat to attend a second summit conference because Khalil has "full authority" to negotiate for Egypt. Nonetheless, the planned absence of Sadat -- at least at the beginning of a second summit conference -- gave rise to speculation that Carter intends to impose the strongest pressure on Begin and the Israelis.

In Israel yesterday, Begin told visiting Dutch reporters that he would not be disappointed if Sadat did not participate in a second summit.

"The issues are between the two countries, not the individuals," he said.

Meanwhile, a spokesman for the Egyptian government said that Egypt "will study carefully President Carter's proposal in light of progress achieved so far at the ministerial Middle East peace talks held at Camp David."

The principal unresolved issue in the talks involves Egypt's insistence that the peace treaty be accompanied by a so-called "side letter" setting out a timetable and target date for completing separate negotiations leading to Palestinian autonomy on West Bank and the Gaza Strip.

Sadat wants a peace treaty with Israel linked to the Palestinian issue to protect himself from charges in the Arab world that he is foresaking the Palestinians. The Israelis have said they are willing to negotiate the question of autonomy, but so far have refused to accept a timetable or target date for completing the negotiations.