The United States and Israel appear to be headed toward their most serious confrontation of the Carter administration on one of the most basic issues of Middle East diplomacy - Israeli withdrawal from the occupied West Bank.

Administration officials, in meetings with members of Congress, American Jewish leaders and journalists, have made no secret of their aprehension about recent positions taken publicly and privately by Prime Minister Menachem Begin and members of his government.

Unless the Israeli stand is quickly shifte - which is considered unlikely - Begin's meetings with President Carter next Tuesday and Wednesday will bring the two nations to a moment of truth with important consequences for the Middle East peace-making process, according to U.S. officials.

Technically, the quesion is the Israeli interpretation of U.N. Security Council Resolution 242, which was adopted by all sides in 1967 as the basis for an eventual Arab-Israeli settlement. Behind the legalities, the heart of the matter is whether Israel is prepared to withdraw from the West Bank in return for peace.

According to American officials, members of Israel's former Labor Party government and several historical accounts, it was clear that the West Bank as well as Sinai and the Golan Heights was included in the essential bargain of Resolution 242 - the return of occupied territory by Israel in exchange for an Arab agreement to permit Israel to live in peace.

Begin, who has taken the strong position for many years that the West Bank is "the land of Israel" and should not be given up, has also said since becoming prime minister last June that Israel remains committed to Resolution 242. But in the past several months he and other senior officials of his government have been saying with growing clarity, according to U.S. sources, that 242 does not apply to the West Bank - in other words, they are not committed to withdraw from it in return for peace.

At the National Press Club last Friday, Carter went out of his way to describe adherence to Resolution 242 as "one of the crucial elements of any progress in the Middle East." He added that "the abandonment of that would put us back many months or years."

Congressional leaders who met with Carter at the White House yesterday reported that he "is concerned about the possibility that the Israelis will renounce Resolution 242 as it affects the West Bank."

Reports from Israel in recent days said Begin may try to sidestep the issue in his meetings here next week, or arrange for U.S. and Israeli leaders amicably to "agree to differ" as they did in Begin's first round of meetings here last July.

U.S. officials, however, said it is not likely that the issue can be skirted or easily turned aside, because in their view the question of withdrawal from the West Bank is fundamental to the future of the negotiations with Egypt and to any potential deal with Jordan.

The Israeli position is that Begin had made an important offer in proposing "self-rule" for the West Bank, and that it is up to the Arabs to the Arabs to make counter-proposals. The Begin government says Israel should not be expected to commit itself to the principle of withdrawal from the West Bank in advance of actual negotiations and an agreement on the details, which are not in sight so long as King Hussein of Jordan will not join the bargaining.

A historic disagreement about the West Bank between Begin's Likud Party and the long-ruling, now opposition Labor Party has been revived by the controversy over Resolution 242. If Begin's West Bank stand is seen in Israel as threatening the collapse of the peace talks with Egyptian President Anwar Sadat, a major domestic political upheaval is likely with unpredictable results.

The position of the American Jewish community on the issue is unclear.American Jewish leaders have had long association with Labor Party leaders and have traditionally backed Resolution 242. On the other hand, they usually back the Israeli leadership that is in power.

Resolution 242, in the interpretation of Israel and the United States, does not specify how much occupied Arab territory must be given back in return for peace. However, the United States has said officially that the territory-for-peace formula applies to "all three fronts" - the Sinai, Golan Heights and West Bank.

Israeli Foreign Minister Moshe Dayan, who will take part in the talks with Carter next week, reportedly has told the United States that Israeli will "consider" giving up some of the West Bank if this is proposed by Jordan's Hussein. But Dayan is reported to have delcared that Israeli will not propose such a thing on its own.