French and Italian paratroopers of the multinational peace-keeping force began to deploy today inside the Palestinian refugee camps on the southern outskirts of West Beirut despite the continued token presence of Israeli troops at the port and airport that has kept U.S. Marines from landing so far.

Palestinian residents, some with tears in their eyes, gave the peace-keeping forces a warm welcome as the first patrols spread out in the dirty, twisting streets of Sabra and Shatila camps where Lebanese civil defense workers were still searching for bodies from the massacre there 10 days ago.

Meanwhile, newspapers here reported that the Lebanese government is considering a plan to reduce the number of Palestinian refugees in the country by making arrangements for them to move to other countries, and eventually to close all the refugee camps.

The peace-keeping force, made up of U.S., French and Italian paratroopers and Marines, was sent back here, after departing abruptly in mid-September, to help the Lebanese Army maintain order and protect the camps from any further attack by rightist Christian militiamen.

The last units of the French and Italian contingents arrived today, bringing the total presence in West Beirut to about 2,200 with 1,200 U.S. Marines scheduled to join them Tuesday or Wednesday. The State Department, which had said earlier that 800 Marines would be sent, said today the total number would be 1,200.

Secretary of State George P. Shultz, at the United Nations, told Secretary General Javier Perez de Cuellar that the United States favors extending the mandate of the U.N. force in southern Lebanon, which expires Oct. 19, for two months. A senior U.S. official told reporters last week that the United States believes the force could be the best instrument for overseeing a demilitarized buffer zone to prevent attacks against northern Israel after an Israeli withdrawal.

White House deputy press secretary Larry Speakes said Monday that the United States is "encouraged by the progress" being made on the withdrawal of Israeli troops from Beirut.

Western diplomatic sources here said the United States was still holding talks with Israel over its demand for continuing access to the Beirut airport, where U.S. Marines are expected to set up their headquarters.

The two sides appeared headed for a compromise that would allow Israeli civilian, but not military, aircraft to land at the airport and an Israeli air controller to be in the airport tower.

Whether the Lebanese government will agree to this compromise, which could prompt many Arab airlines to avoid the airport, was not clear.

A small detachment of Israeli troops with several armored personnel carriers could be seen today stationed near the cross point of the airport's two runways and a similar unit was visible inside the perimeter of the seaport.

Otherwise, the Israeli Army has completely withdrawn from Moslem West Beirut and established lines just south of the airport.

Israeli military spokesmen said yesterday that the Army would officially complete its withdrawal from the western sector by Wednesday and from "all of Beirut," including the Christian eastern sector, by the end of the week.

Italy's Ambassador Franco Lucioli Ottieri said the French and Italians had decided to go ahead with deploying their forces at the urging of newly elected President Amin Gemayel, who was eager for a demonstration of the peace-keeping force's presence in the camps.

The ambassador said the decision was made "on the spot" this morning after a meeting last night of the political committee set up to coordinate the peace-keeping force's activities. It includes the three Western ambassadors and representatives of the Lebanese Army under the chairmanship of Gemayel.

A French Army spokesman said two companies of paratropers -- about 240 men -- established themselves inside the camps early this afternoon and that the rest of the French contingent would be there Tuesday. Another 100 to 200 Italian paratroopers also took up positions in the camp today.

The two camps of Sabra and Shatila, where the massacres occurred Sept. 16 through 18, are adjacent to one another with no clear dividing line. The Italians are guarding the southern approaches to the camps and the French the northern one.

At a press conference, Gen. Jacques Granger, commander of the French contingent, dismissed questions about the possible risks to the peace-keeping force of shooting incidents like those that caused a dozen casualties among Israeli troops here. He stressed his determination to provide security to the Palestinian camps.

Asked about the continuing presence of Israeli troops in West Beirut, Granger replied, "We don't meet them, we simply cross each others' paths."

Ottieri also acknowledged the danger of "some risk" to the peace-keeping force, but he added quickly, "We are becoming more reassured every day."

He noted that the Lebanese Army had deployed in force in the camps as well as throughout West Beirut to help provide protection.

But further uncertainty was cast upon the future of residents still in the camps when local press reports today said the Lebanese government is hoping to reduce the number of Palestinian civilians in Lebanon from its present estimated 500,000 to as few as 50,000.

The report said the government was studying a plan for gradually reducing the number of Palestinian residents and eventually eliminating the camps.

In a first stage, the reports said, camps would be moved outside the capital and other major cities. Later they would be eliminated altogether by moving the residents to other Arab countries. The special status previously given the Palestinian refugees would then also end.

Today at the Shatila camp, bulldozers and trucks were clearing the remains of hundreds of homes wrecked during the war this summer between Israeli and Palestinian forces.

Officials of the U.N. agency reponsible for the Palestinian refugees in Lebanon were discussing with Army representatives the need to set up tents in Shatila.

Meanwhile, about 30 men using rifles and rocket-propelled grenades ambushed and fatally wounded Abu Walid, a member of the Central Committee of Al Fatah, the leading component of the Palestine Liberation Organization, United Press International reported.

[ The ambush occurred in Riyad, near Baalbek in the upper Bekaa Valley. The assailants were unkown. Walid, who had been chairman of the combined military forces in Lebanon, was taken to Damascus' Al Mouasat hospital, but died a few hours later, a PLO spokesman in the Syrian capital said.]