Palestinian guerrilla leader Yasser Arafat proposed today that his encircled troops be dispersed temporarily to other sites in Lebanon until a country of asylum could be found and that the Israeli siege of West Beirut be lifted.

The proposal, already rejected by Israel in an earlier formulation, came amid mounting public pressure from Lebanese and U.S. negotiators to make Israel ease its blockade of predominantly Moslem West Beirut, where 5,000 to 6,000 Palestinian guerrillas remain bottled up.

Some Lebanese political observers view the proposal, which was given to U.S. special envoy Philip C. Habib today, as a maneuver to buy more time in the negotiations on a settlement and to avoid any blame for perpetuating the blockade by not leaving Beirut.

While quantities of fruits and vegetables have come through what has proved to be a porous but variable Israeli blockade, staples such as gasoline, cooking gas and flour have remained in acutely short supply.

More than half of West Beirut's bakeries have closed for lack of fuel and flour. The Health Department, announcing that dump trucks can no longer collect garbage for lack of gasoline, has advised people to burn the refuse piled up on the city's sidewalks. Ambulances reportedly have run out of gas.

Thousands of West Beirut residents gathered at the offices of Prime Minister Shafiq Wazzan today to protest the blockade. A Moslem clergyman warned in a speech that residents would take up arms against the Israeli invaders unless the 12-day-old blockade is lifted.

Wazzan reportedly appealed to Habib today to persuade the Israelis to let in medical supplies, fuel and flour. Previous appeals so far have brought limited results.

Earlier, Wazzan received Arafat's proposal, presented as an interim measure to end the siege of West Beirut, where approximately 300,000 to 400,000 people still live despite repeated Israeli warnings to evacuate.

According to Lebanese sources, Arafat offered to withdraw his forces to the Bekaa Valley in eastern Lebanon or the northern city of Tripoli until a refuge outside Lebanon could be found. Both places are controlled by Syrian troops.

Wazzan conveyed the offer to Habib, whose response was not immediately known. Wazzan told reporters he was optimistic about the offer, which he described as a step that might overcome a key obstacle in the negotiations. The obstacle, essentially the lack of any place to go if the guerrillas evacuate Beirut, arose when Syria refused a week ago to take in the fighters.

According to a Lebanese government minister involved in the negotiations, Syrian President Hafez Assad is demanding a written request from Arafat to bring his forces to Syria, plus endorsement by the Arab League, to avert any future criticism for destroying the Palestinian resistance by aiding a U.S. plan. Assad also is said to want the move as part of a comprehensive plan to settle the Palestinian problem.

In addition, government sources believe the Syrians will demand some guarantee that their strategic interests in Lebanon, notably the Bekaa Valley, will be respected.

So far, the minister said, Arafat has refused to give Assad a written request, preferring an invitation so that PLO forces would be able to go to Syria in a less weakened position in relations with the Damascus government.

For now, Habib's talks are effectively blocked, Lebanese sources said.

They said Arafat's proposal to go to the Bekaa Valley or Tripoli seemed unlikely to be accepted by Israeli leaders, who already have rejected an earlier reported proposal for a two-stage Palestinian evacuation with stops in those two places on the way to Syria. About 3,000 Palestinian guerrillas are believed to be in the Bekaa with Syrian forces after having fled the Israeli invasion of southern Lebanon, and as many as 2,000 are said to be based in Tripoli to guard a camp containing 30,000 Palestinians there.