The Israeli government today denied any knowledge of a possible arrangement reported in Beirut newspapers yesterday under which Israeli troops would pull back from their positions in Lebanon in return for a complete withdrawal of Palestinian guerrillas from the country.

"We don't know anything about it," a Foreign Ministry spokesman said. "We don't make arrangements or deals with the PLO," the Palestine Liberation Organization.

The official said Israel continues to insist that the PLO forces be the first to leave Lebanon, after which there would be a simultaneous withdrawal of Israeli and Syrian troops.

Reports of a possible arrangement involving a partial Israeli withdrawal from positions along the Beirut-to-Damascus highway surfaced over the weekend in the Beirut press. The papers said Lebanon wanted the partial pullback accomplished by Nov. 22 and that such a pullback would have to precede any agreement on establishing a "security zone" in southern Lebanon, which is one of Israel's main demands.

An authoritative Lebanese source said in Beirut yesterday that Lebanon is seeking such a pullback as an opening gesture of good faith in talks aimed at a total withdrawal. But there was no indication whether Lebanese President Amin Gemayel had discussed the proposal with U.S. officials during a visit to Washington last week.

Officials here said that if Gemayel made such proposals during his talks in Washington, the suggestions have not been relayed to Israel by the United States.

The officials said Israel has "no information" that the PLO forces are prepared to leave Lebanon now as part of any negotiated arrangement. They did not rule out completely the possibility of a partial Israeli pullback in connection with a withdrawal agreement, but said they expected any agreement to follow the pattern set in Beirut, in which the PLO forces left the city while Israeli troops remained in place.

Foreign Minister Yitzhak Shamir, who returned to Israel Friday after a three-week trip to the United States, reported to the Cabinet today on his talks in Washington. Officials had little to say about Shamir's report, but the impression was left that the Israelis are less optimistic now on the prospects for the troop withdrawal negotiations than they were before Shamir's trip.

The independent newspaper Haaretz said today that, based on Shamir's discussions with Secretary of State George P. Shultz, Israeli officials now expect the troop withdrawal negotiations to be "long and tiring, stretching over a period of months."

Other officials confirmed that Shamir was told in Washington that the Reagan administration is highly skeptical that the PLO forces will agree to leave Lebanon before either the Israelis or the Syrians -- which is what Israel is demanding as the first condition for its own withdrawal.

Israel is also demanding a formal agreement with the Lebanese government establishing a 25- to 40-mile wide "security zone" in southern Lebanon to protect Israel's northern border communities.

Israeli officials who presented these positions to Gemayel earlier this month say they thought they received his tacit acceptance. Since then, however, the Lebanese president has called publicly for Israel to be the first to withdraw from Lebanon and has said he will not sign a formal agreement setting up a security zone in southern Lebanon.

Gemayel's public stance has also served to dampen the earlier optimism here on prospects for the negotiations, although Israeli officials remain careful in criticizing Gemayel, suggesting that he may be more flexible than his public declarations would indicate.