The Israeli Army today almost completed its withdrawal from Moslem West Beirut, leaving only a small detachment at the airport and port where 700 Italian paratroopers and Marines came ashore to join the French contingent of a multinational peace-keeping force.

But neither the French nor the Italian troops, now totaling 1,400, were immediately deployed in the city. Still awaited is the arrival of 800 U.S. Marines Tuesday or Wednesday.

This afternoon President Amin Gemayel met with Morris Draper, U.S. deputy assistant secretary of state for Near Eastern affairs, and the ambassadors of the three countries providing troops for the multinational force. Diplomatic sources said Gemayel urged the ambassadors to begin the deployment of the peace-keeping force in areas of the city where the Israelis had withdrawn.

The three Western nations are sending about 3,000 peace-keeping troops here following the massacre of hundreds of Palestinian civilians Sept. 16-18 by Christian militiamen. They are to help the Lebanese Army maintain order and guard the camps against other onslaughts.

In Tel Aviv, a military spokesman announced that Israeli forces would leave all of Moslem West Beirut by Wednesday. The only Israeli units that reporters touring the city this morning could spot were those at the port and airport, while others were seen withdrawing from several strategic points.

A Foreign Ministry spokesman in Jerusalem said the Army would pull out of "all of Beirut," including the Christian eastern sector, by the end of the week. But the exact lines to which they would fall back were not made clear.

The spokesman said the airport would be handed back to Lebanese authorities allowing it to reopen after its closure at the onset of the Israeli invasion June 6.

The Israeli decision to withdraw was apparently the result of talks between U.S. special envoy Philip C. Habib and Israeli leaders Friday in Jerusalem. Habib today was in Amman, Jordan, where he met with King Hussein to discuss the Lebanese situation and President Reagan's recent peace initiative.

A spokesman at the Israeli press center at Baabda in Christian East Beirut said today that the Army had ended its search for Palestinian guerrillas and ammunition depots last night.

"It's finished," he said. "First, we want to avoid hard feelings, and second we want to avoid more casualties and problems with the local population. We have had enough, or even too much."

The spokesman said one Israeli soldier had been killed and "about 10 others" wounded in incidents inside West Beirut during the past few days, most of them involving unidentified gunmen who fired on Israeli patrols and positions.

He said the Army would probably officially complete its withdrawal Tuesday after the Jewish Yom Kippur holiday except for the airport, where he said negotiations were still going on over a residual Israeli presence allowing them access to one airstrip.

Lebanese Army sources said tonight that the Israelis were still seeking helicopter landing rights at the airport as well as an agreement to allow them a presence inside the control tower.

Defense Secretary Caspar W. Weinberger, speaking on "This Week With David Brinkley" (ABC,WJLA), indicated that a compromise apparently has been reached with Israel under which Israeli air traffic controllers might operate at Beirut airport.

Weinberger dismissed suggestions of any dispute about Israeli forces and said:

"The simple fact is that, if we are asked to (deploy) in that area and if we are going to do it, the Israelis have to be out. Now there may be some commercial flights at the Beirut airport that may involve some Israeli flights and that may mean an Israeli air controller, but there should not be a military presence."

Weinberger and Nicholas Veliotes, assistant secretary of state for Near Eastern and South Asian affairs, said they expected the U.S. forces to land in Beirut Wednesday. Veliotes was interviewed on "Meet the Press" (NBC,WRC).

As the Israelis withdrew from West Beirut, the Lebanese Army continued to step up its presence, setting up checkpoints and stationing tanks and armored personnel carriers even in the heart of the downtown area. The Army has been detaining hundreds of Arab foreigners without residence permits or valid identity papers, in some cases carrying out house-to-house checks.

Meanwhile, Italian troops began disembarking at the port despite a declaration yesterday by Ambassador Ottieri that "as long as the Israelis are in the port, we and the Americans won't disembark."

Asked why Italy had reversed its position on this issue, Ottieri said there had been "a few positive signs" of Israel's intention to withdraw from West Beirut and added that both the French and Lebanese governments had asked the Italians to come ashore.

"We have decided to come in anyway on the assumption they will leave shortly," he told reporters. "Actually we thought they would be gone by this morning."

Ottieri was on hand to greet the first 350 Italian paratroopers from the San Marco Battalion at the port as they disembarked from the missile ship Perseo and car ferry Canguro Bianco at midmorning. Another 350 Italian Marines landed in the afternoon.

Still very much in evidence 100 yards from the Italian ships were four Israeli armored personnel carriers, several jeeps, an ambulance and perhaps 30 soldiers, who watched the arrival of the Italians in silence.

Ottieri said the Italian troops would be billeted in two schools in East Beirut and would not be deployed to their assigned areas in West Beirut until final agreement had been reached between Israel and the United States over the Israeli withdrawal and the arrival of the 800-man U.S. contingent of the peace-keeping force. Weinberger said last week that the number of U.S. troops sent here might rise to 1,200.

After Gemayel's meeting with Draper and the three ambassadors, Beirut radio said Italian forces had been seen heading for the Galerie Semaan, the main southern crossing point between East and West Beirut.

The French, who have about 700 paratroops ashore, had taken basically the same position of not accepting any deployment before agreement was reached on an Israeli withdrawal.

Today, however, 30 French engineers and as many other paratroops went to a spot just outside the Palestinian Shatila refugee camp to help clear the area of mines at the request of the Lebanese civil defense group working there. A French Army spokesman later denied that this constituted the beginning of the deployment of French troops, saying it was simply a "humanitarian act."

As the Israeli occupation winds down, Israeli Army spokesmen here were giving conflicting accounts about the results of their 12-day stay in West Beirut. Yesterday, one said that the Army killed or arrested "certainly not less than 2,000 terrorists," the number the Israelis originally estimated had remained in the city after the U.S.-negotiated withdrawal of Palestinian guerrillas.

Today, however, another spokesman said the Army had captured only "about 50" Palestinians and Moslem leftists so far and refused to estimate the number killed.

Both spokesmen agreed that the Israelis had seized each day an average of 750 tons of arms and ammunition stored by Palestinian guerrillas and leftist militiamen in West Beirut. They said 150 trucks a day had been used to haul the war materiel south to Israel. The Lebanese Army had also seized huge amounts, they said.