Another Lebanon dilemma: who wants the guerrillas?

So far no Arab country has opened its door to Palestinian guerrillas and civilians trapped by the Israeli Army in western Beirut.

There seems hardly an Arab country stable enough to welcome 6,000 armed or unarmed guerrillas. Jordan still remembers the bloody ''black September'' of 1970, Egypt is severely overpopulated as it is (and presumably the guerrillas' families would have to accompany them), Syria has a sizable Palestinian refugee population of its own and a repressive regime that would crush any of the Palestine Liberation Organization's remaining independence.

Gulf states are small and vulnerable enough to subversion at present. Yet the guerrillas' welcome clearly has been worn out in Lebanon. Israel demands the guerrillas leave.

The increasingly powerful right-wing Phalange demands, at times, that all Palestinians in Lebanon leave. If just the fighters go, the 600,000 civilians remaining might be set upon at some future date by Phalangists or even by Shiite Lebanese with whom there have been street wars in the recent past. In short, on June 30 it seemed that fighting in Beirut would soon resume unless some outside Arab country took the risk of housing the Lebanese Palestinians.

Israel radio quoted Israeli Prime Minister Menachem Begin as saying under no circumstances would Palestinian guerrillas be allowed to stay in west Beirut. One day earlier, Mr. Begin said guerrillas could carry their light weapons with them if they would depart.

Officers at the Israeli command in the Beirut suburb of Baabda said June 30 that neighboring countries might be much less inclined to accept armed Palestinians than unarmed ones.

''We have given them a way of preserving the soldier's honor by letting them keep their weapons, not leave with their hands up,'' Israeli Capt. Zvi Yeshurun told the Monitor. ''But they must go out of the country. They cannot just stay in Lebanon and redeploy.''

''Who,'' he asked, ''will want 6,000 men armed with Kalashnikovs (Soviet machine guns popular with guerrilla fighters)?''

Palestinian officials are believed to have argued that a minimum concession Israel could make would be to withdraw 5 to 10 kilometers from Beirut to let Palestinians cross into Syria. Israeli Col. Paul Kader said Israel would not withdraw, but ''you will be absolutely sure we will respect whatever agreement can be reached regarding safe passage.''

If efforts to reach an agreement satisfactory to Israel fail (and Israel radio June 30 said Israeli leaders were pessimistic about diplomacy), the next military step, Israeli officers said, was not necessarily a storming of west Beirut by their soldiers. That would cause high Israeli casualties and be unpopular at home.

One officer suggested that Israel could tighten the siege of western Beirut. ''People are not thirsty now,'' he said. ''They are not lacking water. But people who are thirsty may change their minds.''

This officer also said bombardment of Palestinian areas of west Beirut might be resumed. He said assaulting the city all-out would be a last resort. But cutting water and electricity in west Beirut would affect Phalangist east Beirut. And Palestinian bunkers are strong enough to withstand even the heaviest Israeli bombardment, military experts say.

A United Nations official told the Monitor he thinks Israeli soldiers might try to rush through Palestinians camps on Beirut's south side after heavy bombardment and stop short of PLO headquarters on Fakhani Street in Beirut proper. Then, he said, PLO leaders and guerrillas would be trapped in a smaller area and Israeli commandos could mount ''Entebbe raids'' into Beirut. (The Entebbe raid was the 1976 freeing of Israeli hostages held in Uganda.)

A tour of the Beirut outskirts June 30 showed that Israeli forces were taking up new strategic positions overlooking Beirut. At one spot Israeli tanks moved into high ground formerly occupied by the Phalange. They had their cannons pointed on trajectories that would send shells into west Beirut.

Military traffic was heavy, but soldiers did not seem on particularly high alert. The UN official said, however, that a group of Israeli Merkava tanks, especially suited for street fighting, had been sent into Lebanon.

Along Israeli-PLO confrontation lines there was occasional light firing, but it was not sustained. In the mountains east of Beirut, artillery duels were reported between Israeli-Phalange forces and Syrians near the town of Hammanah.