Israel, in what amounted to an ultimatum, demanded today that all Palestinian guerrillas in West Beirut surrender their arms to the Lebanese Army and leave for Syria by passing through Israeli lines on the Beirut-to-Damascus highway.

There was no immediate reaction here to reports from Beirut that PLO leader Yasser Arafat had in principle accepted Israel's demands.

Defense Minister Ariel Sharon denied that Prime Minister Menachem Begin had, during his visit to Washington last week, promised President Reagan not to invade West Beirut, as stated by White House spokesman Larry Speakes.

The Israeli Cabinet pledged to maintain the current two-day-old cease-fire and publicly set no deadline for fulfillment of the demands. But with Israeli troops ringing Beirut and Israeli warplanes dropping leaflets warning civilians to flee, its decision seemed intended as a threat of an all-out ground assault on West Beirut unless the 5,000 to 6,000 beleaguered guerrillas there comply within a short time.

Meanwhile, an Israeli military official acknowledged that Israel has used U.S.-supplied cluster bombs in Lebanon, saying that they were used against "organized resistance" and not against civilians. The acknowledgment appeared likely to raise again the question of whether Israel has used the devastating weapons in violation of the conditions it accepted when the United States supplied them. Details on Page A15

The Israeli stand also was interpreted as a warning to the United States that special U.S. envoy Philip C. Habib must arrange a guerrilla surrender acceptable to Israel soon if Washington expects the Israeli Army to hold off storming West Beirut to deal a final, bloody blow to the Palestine Liberation Organization.

"We obviously cannot wait long," said an authoritative government source. "We cannot wait for weeks and weeks for an answer. But whether it is a question of days, hours or a week, I cannot tell you. The Cabinet has not decided."

Begin is reported to have come under strong pressure from Washington in the past several days to give Habib a chance to work out a disarming of the guerrillas through peaceful means. At the same time, Sharon and other hard-line members of the Israeli Cabinet are reported to be urging a swift attack to finish off the guerrillas quickly lest Friday's change in U.S. secretaries of state evolve into a shift in U.S. policy, that so far has been considered supportive of Israel's moves in Lebanon.

The Cabinet decision today appeared to be a compromise. It promised to maintain the cease-fire for an undefined period during which Habib can continue his efforts, but it kept the threat of an attack in the forefront. As explained by Israeli informants, Begin's government feels that such an assault is the only answer if Habib cannot persuade Arafat and his followers to surrender and leave Lebanon.

If Habib's negotiations "do not succeed, I would ask Mr. Shultz, or even Mr. Reagan, what do they propose?" a government official said, referring to the president and Secretary of State-designate George P. Shultz.

The Israeli demands outlined today seemed to harden the Israeli position as previously defined. They said all guerrillas, "without any exceptions," must leave Lebanon. Earlier formulations from high government officials had spoken only of the leadership and the "core" of PLO fighting forces.

On the other hand, the new demands appeared to leave open the possibility of guerrillas remaining in Syria, where they could rearm later. Earlier demands had specified they must be expelled to a country not bordering Israel. The shift seemed to reflect confidence that Syrian President Hafez Assad would prevent guerrillas from attacking Israel from Syrian soil, if only to avoid reprisal attacks on Syria.

Diplomatic sources in the Syrian capital of Damascus said Syria would be reluctant to take PLO guerrillas into its territory. "Syria does not want the country nor the capital to become a target for Israeli raids," Washington Post correspondent Leon Dash quoted a knowledgeable Asian diplomat as saying.

These sources added that the PLO itself would also be reluctant to move into Syria because its guerrillas would not have the freedom to operate as they had in Lebanon. "The Syrians would bring them under tight control here," a Western diplomat said, Dash reported.

The Cabinet position urged the Lebanese Army to enter West Beirut and assure security there as well as accept the Palestinian surrender. It specified, however, that the passage of unarmed PLO guerrillas to Syria should take place "under the protection of the International Red Cross."

"The Israeli Defense Force will ensure that in the sector of the road which is under its control, the column will have safe passage," the Cabinet statement said. "If the terrorists prefer an alternate route, this will be made possible for them by the Israeli Defense Force."

"Only then, when they go out, when this is achieved," can negotiations on Israeli withdrawal and a political settlement in Lebanon begin, a government official explained. It was not clear whether this coincided with Habib's efforts in Beirut. But Israeli officials depicted the idea as "not far from the American position."

The Lebanese Army for the past seven years has been considered a Christian institution by many of Lebanon's Moslems. As such it could encounter resistance from some Lebanese in West Beirut even after the guerrillas are gone, particularly from leftist groups allied with the PLO.

In the official Israeli view, however, Lebanese Moslems would welcome the authority of their own Army despite the bitter heritage of the civil war, when the Army split along Moslem-Christian lines. This was reflected in the Cabinet communique, which said:

"With the liberation of West Beirut and the reunificaton of the Lebanese capital, the political negotiations between all the parties concerned will begin with a view to reaching an agreement that will guarantee the territorial integrity of Lebanon, the departure of all foreign forces from that country, its independence and the peace of its inhabitants. This agreement will ensure security and peace of the Galilee and its inhabitants, of Israel and its citizens."

The language of the communique also suggested that Israel include a role in setting up a new Lebanese government as one of the aims of its war. Opposition leaders have severely criticized the Begin Cabinet for what they charge was deception in first depicting the invasion as a way to protect northern Israel and then broadening its goals to comprise total destruction of the PLO and "a new order" in Lebanon friendly to Israel.

The opposition Labor Party's number two leader, former prime minister Yitzhak Rabin, said today after a briefing at the parliamentary Security and Foreign Affairs Committee that he is convinced Israel cannot realize its political ambitions for Lebanon.