Amid reports from elsewhere of a massive Israeli military buildup on the Lebanese border and expectations of an attack on Palestinian guerrilla strongholds, the frontier today was eerily tranquil, with no visible movement--except for hundreds of Israeli tourists on Passover holiday outings.

Residents of this hilltop border town, which overlooks a broad expanse of southern Lebanon from the northernmost point of Israel, reported no unusual military movements. There was no sign of the two armored divisions and 40,000 troops that have been reported by spokesmen for the Lebanese government and the Palestine Liberation Organization.

The border road that runs south from Metullah and then west toward the Mediterranean seaside also revealed no sign of unusual military activity. Neither did the highway north from Tiberias--usually favored by the Israeli Army for transporting tanks and armored personnel carriers to the north.

However, reporters were not permitted to go across the border into the enclave controlled by Lebanese Christian militias led by Maj. Saad Haddad. It was likely that if there has been a buildup of Israeli forces it would be in the vicinity of Marjayoun, the northernmost town in the enclave.

There is a six-mile-wide gap there between the Nigerian and the Norwegian battalions of the U.N. peace-keeping force through which Israeli land forces have moved during previous incursions against PLO strongholds. The gap is not within sight of Metullah, but no troop movement could be seen on its approachs.

There was an almost festive atmosphere along the border as hundreds of picnickers crowded the nature preserves along the frontier, and hundreds more visited the "good fence" crossing point used by Lebanese civilians who commute to jobs in Israel.

Six tourist booths were doing a brisk business in selling "free Lebanon" T-shirts as visitors crowded onto an observation platform overlooking the crossing point. Beyond, Lebanese farmers tilled the fields and local traffic moved unhurriedly, seemingly unmindful of a possible outbreak of hostilities.

Israeli Foreign Minister Yitzhak Shamir, in an interview published in the West German newspaper Die Welt, was quoted as saying that Israel will strike against the PLO in retaliation for the murder in Paris last week of Yacov Barsimantov, a second secretary in the Israeli Embassy.

Prime Minister Menachem Begin's spokesman, Uri Porat, while refusing to comment directly on whether an invasion was likely, said that Palestinian guerrillas "have good reason for their panic and hysteria" over the threat of an Israeli raid into Lebanon, The Associated Press reported from Tel Aviv.