Israel's Cabinet formally approved the Egyptian-Israeli peace treaty today, clearing the way for expected endorsement by the parliament later this week and signing ceremonies in Washington on Monday.

The Cabinet also unexpectedly authorized Prime Minister Menachem Begin to recommend to the Knesset, the Israeli parliament, that it endorse the treaty. Begin, after President Carter's trip to Cairo and Jerusalem, had said he would let Knesset members vote their conscience without a recommendation from the government.

The Cabinet defused a potential crisis in Begin's Likud coalition by striking a compromise with the pivotal National Religious Party and appointing a special 11-member ministerial committee to "elaborate proposals" on what form Palestinian autonomy will take in the West Bank and Gaza.

The three National Religious Party ministers, expressing fears that the autonomy plan will inevitably lead to a diminished Jewish presence in the occupied territories, had threatened opposition to the treaty by the party's 12 Knesset members.

The Cabinet vote was 15 to 2, with Agriculture Minister Ariel Sharon and Transport Minister Chaim Landau casting the only dissenting votes. Both have been vocal and consistent right-wing critics of the peace treaty, although Sharon had shown signs recently of moderating his position.

Begin and his wife, Aliza, are expected to leave Israel Friday for Washington, a day after Foreign Minister Moshe Dayan's departure to discuss bilateral aspects of the accord with U.S. officials and to be on hand for the signing. On Saturday, a special charter flight is to bring eight other ministers, top government officials, former prime minister Yitzhak Rabin, opposition Labor Party leader Shimon Peres and other Israeli public figures.

President Anwar Sadat's Egyptian Cabinet approved the treaty unanimously last week.

Endorsement of the treaty by a large majority of the Israeli parliament Wednesday or Thursday appeared assured, with political factions from left and right adopting resolutions in support of the accord, but some voicing reservations about the autonomy plan for the West Bank and Gaza.

The Labor Party Central Committee voted to impose party discipline on its 32 Knesset members in support of the pact. This means the members will not even be permitted to abstain. Nevertheless, a few may express disapproval by failing to be in their seats when roll call is taken.

The Labor bench also will introduce a motion, sure to be defeated, calling for territorial adjustments in the occupied territories and creation of "security zones" around Jewish civilian settlements.

The four members of the left-wing Mapam faction of the Labor alignment and the two Sheli, or Peace Party, members have voted to support the treaty as have the four members of the Agudat Yisrael Party. Also, the seven members of Deputy Prime Minister Yigael Yadin's faction of the former Democratic Movement for Change have indicated support.

In the Likud bloc of 43 members, at least 30 are expected to vote for the accord, including 14 Liberal Party members whose Executive Committee has endorsed ratification. Most dissension in the Likud is expected to come from members of Begin's own Herut Party and the rightist Laam faction -- two splinter groups that are divided over the treaty.

The compromise with the National Religious Party ministers appeared to assure that the party's 12 Knesset members also will support the treaty, giving the government between 80 and 85 of the 120 Knesset members.

The party has asked for further discussion by the special Cabinet committee on Israeli control over water resources in the West Bank, continued Jewish settlement, application of Jewish law over the settlers, use of Israeli Army troops to protect West Bank and Gaza settlers and the contention that autonomy should apply to individual residents rather than the territory they inhabit.

Significantly, the special ministerial committee includes Interior Minister Yosef Burg and Education Minister Zevulun Hammer, both of the National Religious Party. It also includes Sharon, but not Landau, the two ministers who voted against the pact today.

The makeup of the committee and the principles of autonomy that will be advanced by at least some of its members appeared to presage a hardline Israeli stance when negotiations begin in a month on autonomy for Palestinians. It was expected all along that Israel would begin the talks with a minimum of concessions, and the stands outlined by the National Religious Party are similar to recommendations drafted two months ago by a special interministerial committee headed by the director general of the prime minister's office, Eliahu Ben-Elissar.

Although the Knesset vote seems a foregone conclusion, Begin has said that if the treaty were rejected his coalition government would resign under the parliamentary tradition of collective responsibility. The prime minister also has suggested he would quit unless there is majority support within the Likud. When the original Camp David agreements were approved by the Knesset in September, it was done so only with the support of the Labor alignment.