The Israeli Cabinet again postponed completion of its debate on the future of the occupied West Bank and the Gaza Strip, saying it will reach conclusions later in the week on key questions posed by the United States on the future of the territories after the end of a proposed five-year autonomy plan for Palestinian Arabs.

Three proposals reportedly were submitted during yesterday's five-hour meeting, but several Cabinet ministers who did not get a chance to debate asked for an extension. Wednesday was mentioned as likely for resumption of the debate.

The proposals were submitted by Foreign Minister Moshe Dayan, defense Minister Ezer Weizman and minister without portfolio Haim Landau. Final decisions on the future of the occupied territories has been put off repeatedly, first because Israel sought to reassess its position following the U.S. Senate approval of the sale of warplanes to Egypt and Saudi Arabia, and later because Prime Minister Menachem Begin became ill.

The Cabinet, which appears divided on the issue, has been seeking to draft answers to two questions given to Dayan last April by the State Department: whether final settlement of the issue of West Bank and Gaza sovereignty will be possible after five years of limited Arab self-rule, and how the Palestinians will achieve a measure of political expression at the end of the period.

Although details of the proposals have not been disclosed officially, Dayan was said to recommend that Israel reply on the basis of its interpretation of U.N. Resolution 242 - which calls for Israeli withdrawal from occupied territories. Isareel has interpreted that not to mean a total withdrawal.

The Dayan plan also reportedly provides an active role for Jordan in the self-rule period, which presumably would restore some sympathy in Washington for Israel's negotiating posture.

Weizman's plan is said to stress the importance of negotiating with the Arabs at all levels, while Landau's proposal - described as the most hard-line of the three - reportedly proposes that the Cabinet tell the United States that the only acceptable plan is limited self-rule as proposed by Begin and that at the end of the trial period Israel will make up its mind on the basis of its five-year experience.

The Labor Party, which controlled the government from the founding of Israel until Begin's Likud coalition gained power a year ago, released independently a peace plan that emphasized the need for territorial concessions but does not object to the interim autonomy proposed by Begin. Labor officials said their views on autonomy are, in effect, a bridge between their peace plan and the position of the Cabinet members from Begin's Likud party.

At least two hours of yesterday's meeting were taken up with discussions of defense and security matters, including a report on an early morning attack on the Mechola Israeli settlement on the West Bank of the Jordan River.

Officials reported that four Palestinian guerrillas climbed over a fence of the settlement, opened fire on two armed guards with automatic weapons and three grenades. Three of them climbed back over the fence and escaped, and one was killed by gunfire from the settlement. No Israeli casualties were reported.

The guerrillas reportedly left two small Palestine Liberation Organization flags behind. A search was called off when footprints, a machine gun and another PLO flag were found on the riverbank, indicating that the guerrillas made their escape across the Jordan. In Beirut, a spokesman for Al Fatah claimed responsibility for the attack.