The Palestinian guerrilla movement, increasingly involved in Lebanon and its bloody quarrels, for the first time has begun to encounter significant resentment among the Moslen Lebanese who have been firm allies for more than a decade.

High-ranking officials of the Palestine Liberation Organization and Lebanon's top Moslem leaders, including some who have sent militiamen to fight alongside guerrillas for seven years of hostilities here, regard the development as a major setback for the PLO, which is already violently opposed by Lebanese Christian groups.

Palestinian leaders and their Moslem allies alike remain confident that the resentment will diminish in time and that it will not lead to a Moslem-Christian reconciliation aimed against the guerrillas, who have made Lebanon their base since being chased from Jordan in bloody fighting in 1970. This is due to the bitter political split between Lebanon's Christian and Moslem leaders -- widened by the civil war -- and a profound reserve of sympathy for the Palestinian people left without a home by the creation of Israel.

But they acknowledge that it dangerously weakens popular support, without which the guerrilla movement cannot effectively operate against Israel from Lebanese bases. In addition, they say, it creates a risk that Lebanese leftist militias would remain neutral if tensions between Syria and the PLO escalate into combat as they did in 1976, when the militias fought alongside guerrillas.

"Any conflict between the Palestinians and the Syrians would weaken the [Lebanese] National Movement, and that is why it is in our interest to remain neutral," said Walid Jumblatt, head of the overall National Movement grouping Lebanon's main leftist political militias and the PLO.

Jumblatt publicly has described recent tensions between Lebanese Moslems and the PLO as a "crisis of confidence," calling on Yasser Arafat's PLO leadership to show more respect for Lebanon's own concerns when they differ from those of the Palestinians. The Druze leader spoke out after sharp clashes between Moslem militias and PLO guerrillas last week in this port city 25 miles south of Beirut.

Two persons were killed and 17 wounded in the fighting, which erupted after local militiamen killed a guerrilla officer and PLO security forces carried out a revenge raid. More important, the clashes did extensive damage to the main commercial street in Sidon's ancient Shakariyeh market area, bringing to the surface a previously muted bitterness among local residents whose affairs largely have been run by PLO leaders since central state authority broke down.

"The Palestinians do anything they want," complained a Sidon merchant surveying the burned-out street. "They burn anything that comes into their grip. We've got to speak out."

"The [Lebanese civil] war started here," said another Sidon resident, recalling the Moslem defense of the PLO in 1975. "People here in Sidon told the Palestinians to come, that they were welcome. But not for them to mount on our backs."

The Sidon incidents appear to have broken a silence about broader resentment against the Palestinians, less intense but equally troubling. One Lebanese Moslem, an ardent supporter of the Palestinians, said some of it may grow from PLO refusal to pay for Lebanese homes destroyed in Israel's Beirut bombing last July that killed about 300 persons, most of them Lebanese. Conversations with a number of Lebanese Moslems indicate that the resentment also arises from simple weariness with the bloodshed and chaos that, although guerrillas may not be directly responsible for it, accompany the PLO presence in Lebanon.

"People are unhappy in the streets," said a top Lebanese leftist leader with close ties to the PLO. "The Palestinians did the same stupidity in Jordan [in 1970]. And now they are doing it in Lebanon. What happened in Sidon is very sad and disquieting for the Palestinians."

Another prominent Moslem leader, with high-level experience in dealing with PLO issues, said: "Sidon was very harmful to the Palestinians. I hope it taught them a lesson." Like his colleague, he requested anonymity, a reflection of PLO power in the streets and popular support.

The irritation among Lebanon's traditional Sunni Moslem population comes after a series of clashes with the newly assertive Shiite Moslems and their increasingly well-armed militia, Amal. Palestinian guerrillas battled Amal gunmen last month in a string of southern Lebanese villages where PLO troops were positioned to confront Israel, and later the combat spread to Beirut and surrounding refugee camps.

Amal was formed several years ago to protect Shiite Moslems who often are victimized by the Palestinian-Israeli conflict in southern Lebanon, sometimes by Israeli shelling or bombing and sometimes by Palestinian guerrillas. Strengthened by the Shiite revolutions in Iran, Amal also has been aided by Syrian peace-keeping troops in a reflection of the alliance between Damascus and Tehran.

Palestinian officials say Syrian military leaders have guided Amal activities against guerrilla forces on occasion to exercise influence over PLO policies here. Some PLO officials expect more Syrian pressure in coming months as President Hafez Assad works against Arab reconciliation with Egypt.

Against this background, some PLO officials are saying privately that Arafat's lieutenants must be more careful in dealing with their traditional allies in Lebanon. The PLO presence should be more discreet, they say, and the guerrilla leadership should make a greater effort to remain aloof from Lebanese affairs.

"The leadership has been consumed by everyday [Lebanese] life troubles," a ranking PLO official said. "Sometimes I think they are not spending enough time on their far-reaching strategy."

He added: "Lebanon is quite a tempting country. Life is very soft and nice. There are a lot of women and liquor. Things would have been different if the boys were still in the woods of Jordan."

But, he said, most of the tension results from the fact that Palestinians and Lebanese -- each side with its own cause -- have been living together for too long in difficult conditions largely caused by the fact that Palestinians are present in Lebanon.

"I remember 10 years ago, when people here would see a Palestinian passing in a uniform, they would look on him as a champion," he said. "Now it's the ordinary thing -- and they may see him in a bar."