President Carter reported yesterday that although gains have been made for convening an Arab-Israeli peace conference and for concluding a new American-Soviet arms control pact, neither goal is is in sight.

At his news conference the President stressed the complexities of these two most intractable subjects on his foreign policy agenda, under intensive negotiation at the White House for the past two weeks. In both cases he deflated speculation that solutions are imminent.

The Arabs and Israel, Carter said, both "are to be congratulated" because they "have come a long way" in searching for a formula to reassemble a Geneva peace conference. But "widely divergent views" remain, especially on who will represent the Palestinians in such a meeting, he said, and "I cannot predict a final outcome."

Similarly, Carter said, "We have been encouraged recently by the cooperative attitude of the Soviets" on negotiating a new accord in the nuclear stragetic arms limitation talks (SALT), projected in 1974. "So we are making some progress," Carter said, but "I wouldn't too optimistic about an early settlement" and there is no plan at this time for a Carter meeting with Soviet leader Leonid I, Brezhnev.

The President has been heavily engaged in both these negotiations that have switched back and forth over the past two weeks, here and at the United Nations in new York, where Secretary of State Cyrus R. Vance is continuing the talks. Carter has spent considerable time talking with the foreign ministers of the Soviet Union, Egypt, Israel, Syria and the special envoy of Jordan.

In the Middle East negotiations, Israel has been getting increasingly concerned that the Carter administration is leaning more heavily upon it than upon the Arab nations for a compromise. The Israelis are saying, in Jerusalem and in New York, that they will yield no further on Palestinian representation in a single unified Arab delegation at a Geneva conference.

Carter noted that "there are some differences among the Arab nations" also.

However, the negotiations are stuck most, as Carter recounted, on Arab insistence that the Palestine Liberation Organization is the "only legitimate representative" of the Palestinian people. Israel refuses to bargain with the PLO because it "has been identified in the past as committed to the destruction of the nation of Israel."

Carter did not mention specifically that, in an attempt to circumvent this standoff, the United States has pushed for including Palestinians in the single, unified Arab delegation.

Israel agreed to a ceremonial meeting of the unified delegation, but said it could not include known PLO members. In addition, Israel has said that after the first meeting, the Arab delegation would have to divide into states, such as Egypt, Syria and Jordan, with Palestinians in the Jordanian delegation. Israel said it will never accept a Palestinian state.

That United States, Carter repeated, has pledged to Israel that it will "not negotiate with, or deal directly with the PLO" until it adopts U.N. Resolution 242 of 1967, "which includes a recognition of the right of Israel to exist."

In a new attempt to nudget the PLO, Carter said:

"If the PLO should go ahead and say, 'We endorse U.N. Resolution 242, we don't think it adequately addresses the Palestinian issue because it only refers to refugees and we think we have a further interest in that,' That would suit us okay."

When asked what "assurances" he would give the PLO in that event, Carter said only that "We will begin to meet with them and to search for some accommodation and some reasonable approach to the Palestinian question if they adopt 242 and recognize publicly the right of Israel to exist."

"I certainly don't think they are the exclusive representatives of the Palestinians," Carter said. He said there are mayors and local officials in the Israeli-occupied West Bank of the Jordan River "who may or may not be members of the PLO." These are the Palestinians whom Israel has said it would accept, in a Jordanian delegation, to discuss Palestinian problems."

At the United Nations yesterday, PLO spokesman Shafik Elhout said Carter's latest offer of dialogue with the PLO is unacceptable. He said, "This is not a new proposal, and much as we look forward to a dialogue with the United States, we cannot accept Resolution 242, as we have said before." He said the PLO seeks "a free, unfettered and unconditional dialogue with the United States."

In discussing his two rounds of talks with Soviet Foreign Minister Andrei A. Gromyko on nuclear arms control, Carter said the Soviets "have been fairly flexible in their attitude, and we have tried to match their cooperative stance."

He disclosed no details. The Soviet Union is believed to have given some ground to American insistence that the new agreement must permit considerable numbers of American long-range, air-launched cruise missiles. Carter said, however, that "we have not completely resolved" the cruise missile dispute, nor another he was asked about concerning mobile, intercontinental missiles.

There is "no restraint" on either of these weapons, Carter noted, in the existing, five-year U.S.-Soviet agreement on limiting intercontinental missiles and bombers which runs out Monday. Both nations have agreed to honor those arms ceilings until a new accord is reached.

Carter said "we have narrowed down the differences" for a new SALT agreement "to a relatively small number" of issues, but those, he said, "could take quite a long time to resolve." Negotiations are returning to Geneva this weekend "to try to eliminate as many of the differences as possible, he said. "So reasonable progress has been made."