Senior Israeli officials, reaffirming a statement by Chief of Staff Gen. Rafael Eitan, said today that Israel has decided to launch a "political" effort to remove the leftist Morabitoun militia from Beirut following the evacuation of Palestinian guerrillas from the city.

The officials said the Lebanese Moslem organization is the Palestine Liberation Organization's "closest ally in Beirut" and has taken control of most of the heavy weapons that the guerrillas are leaving behind as they withdraw from the Lebanese capital.

Israel has no intention of making a military move against the leftist miltia, the officials said, but will "certainly work to get them out of Beirut" through political measures, possibly involving contacts with U.S. special envoy Philip C. Habib.

Israel's concern over Morabitoun was first raised yesterday by Eitan in an interview with Israeli military correspondents. Israeli radio quoted the chief of staff as saying that Morabitoun "is no different from any other terrorist organization as far as Israel is concerned" and would therefore not be allowed to remain in the city.

When Eitan made these comments, it was not clear whether he was reflecting Israeli government policy or merely expressing his own opinion as a military leader.

Questioned today about Eitan's statements, senior officials made it clear that the chief of staff's views are also those of policy makers.

Calling Morabitoun "an extremist organization that poses a security threat," an official said it was the acquisition of the PLO's heavy weapons by the leftist militia that led Israel to conclude that "they should be out of Beirut."

Asked on what grounds Israel would seek the removal of a Lebanese organization from the Lebanese capital, the official said that Israel has information that "many of their members are not Lebanese."

According to Israeli officials, Morabitoun has about 1,500 members and is the most powerful of the leftist militias in Beirut. The organization has taken over many of the positions abandoned in the city by the PLO and it could pose a serious threat to the authority of the Lebanese Army in the capital.

Israeli officials said that as far as they know the PLO has not turned over any of its heavy weapons to the Lebanese Army as required by the evacuation plan crafted by Habib. But they suggested that Israel still prefers to allow the PLO evacuation to continue uninterrupted rather than attempting to enforce the provisions of the agreement dealing with weapons.

Meanwhile, officials sought to downplay what was described in the Israeli press today as a sense of "alarm" in Jerusalem following Defense Minister Ariel Sharon's meetings with Reagan administration officials in Washington.

Members of the Israeli Cabinet were described as most upset by reports that Secretary of State George Shultz had suggested to Sharon that Israel would have nothing to fear from a demilitarized Palestinian state in the occupied West Bank. This prompted one Cabinet minister to assert that any such change in the Camp David peace accords would leave Israel free to annex the West Bank and Gaza Strip.

Officials said today they understood that Shultz, as a new secretary of state, was reviewing all possible options regarding U.S. policy in the Middle East.

[In Washington, State Department spokesman John Hughes said that Shultz, in his talks with Sharon, had not proposed creation of a Palestinian state.]