Israeli officials believe that even if agreement is reached with Egypt on a declaration of principles for a Middle East peace settlement, the process may still founder on Jordanian King Hussein's refusal to join the negotiations.

Foreign Minister Moshe Dayan told a closed session of the Israeli Parliament's Foreign Affairs and Security Committee Wednesday that the reason Egyptian President Anwar Sadat appears to be backing away from o U.S. compromise on the declaration is because it remains unacceptable to Hussein.

Israeli officials say Sadat appears to have decided that he cannot conclude a peace agreement with Israel unless Hussein at least agrees to enter the negotiations.

Hussein, in an interview earlier this month, listed as conditions for joining the negotiations Israeli agreement to total withdrawal from all occupied Arab territory, Palestinian self-determination, the right of Arab refugees to return to homes abandoned in Israel and security guarantees for all states.

Israel has termed these conditions "impossible."

U.S. sources said the United States has assured Sadat that it will make a major effort in the weeks ahead to persuade Hussein to agree to join the peace negotiations.

But an Israeli source in Washington yesterday expressed doubt that even if "we agree on the general principles (with Egypt), it will be sufficient to have Hussein enter the picture, or for Sadat to go ahead with the negotiating process."

"The king has to have a poor sense of timing," the Israeli said. "He entered the war at the wrong time in 1967, and he's staying out of peace at the wrong time in 1978."

The Israelis also renewed their opposition yesterday to the Carter administration's plans to sell advanced military warplanes to Saudi Arabia and Egypt as part of a package that includes additional U.S. jets for Israel.

The Israeli source said the Carter administration's decision to link the sale of 60 F15 fighters to Saudi Arabia and 50 F5E fighters to Egypt to the sale of 90 F16 and F15 warplanes to Israel demonstrated that "those individual deals cannot possibly stand on their own."

The administration presented the deal as a package in an effort to prevent Israel's friends in Congress from blocking the sale of the planes to Egypt and Saudi Arabia.

"By linking it in a package, it complicates the whole situation," the Israeli said. "We are opposed to the very notion of a package deal. We feel it is not consonant with commitments made to Israel, nor to the threat."

the source denied, however, the suggestion that relations between Israel and the United States are at a low.

"I've seen better periods," he said. But he said that over the past five years he had also observed "ups and downs of much greater depth."