The leadership of the Palestine Liberation Organization today criticized President Reagan's Middle East peace plan but stopped just short of the formal rejection of it advocated by some of the more radical PLO members.

In a sometimes heated nine-hour meeting of the PLO's 56-member Central Council, the Reagan initiative was repeatedly attacked because it did not openly acknowledge the PLO as the representative of the Palestinian people or the right of Palestinians to have an independent state.

One of the strongest criticisms of the U.S. plan, according to a PLO official who attended the meeting, came in a speech by Chairman Yasser Arafat. The council gave Arafat a vote of confidence and a green light to continue the cautious diplomacy that has characterized his actions since the PLO was forced out of Beirut at the end of the summer.

PLO sources said that while attacking the Reagan plan, Arafat insisted on the need for the PLO to continue trying to open a diplomatic dialogue with the United States.

In Washington, State Department Middle East experts attempted to downplay the significance of the PLO meeting, saying "no one expected them to come out and endorse the Reagan initiative."

It is clear, however, one official said, that the PLO action Friday "does not move the process forward," adding that, "It doesn't mean the end of the ball game. The Palestinian council still could do something."

In a final communique issued by council Chairman Khaled Fahoum this morning, the PLO declared that "the proposals of American President Reagan do not satisfy the inalienable national rights of the Palestinian people led by the Palestine Liberation Organization."

The reason they did not, Fahoum said, was that the "Reagan plan ignores the right of our people to self-determination and to establish an independent Palestinian state under the leadership of the PLO, without which there can be no just and lasting settlement in the Middle East."

The Reagan plan, proposed Sept. 1, envisages an Israeli pullback from the West Bank of the Jordan and the Gaza Strip, territories it has occupied since 1967.

It also specifically rules out any PLO participation in negotiations for the territory's return or the establishment of an independent Palestinian state.

In a speech during the session, which ended early this morning, there was debate about various aspects of PLO policy, including the chairman's chilly relations with Syria, his conversations with Hussein and approaches to renewed relations with Egypt. There was no question of Arafat's leadership being challenged, however.

Even the radical Popular Front for the Liberation of Palestine, a frequent critic of the chairman's policies in the past, gave Arafat its support.

"It was a victory for Arafat," said a senior PLO member today. "There was no rebellion against his policy. He was given a vote of confidence."

But Arafat's vote of confidence in the Central Council, a body made up of the organization's leadership, labor union and professional association chiefs and various Palestinian notables, was not exactly a consensus on where the PLO should go next. There was still little sign that the various guerrilla chiefs, who are the most influential members of the PLO, had been able to agree on a common policy for the clearly difficult post-Beirut era.

The absence of a consensus that would allow the convening of a much-delayed meeting of the Palestinian National Council, the PLO's equivalent of a parliament in exile, was evident in Fahoum's statement today that a new round of "intensive meetings" among PLO leaders would be held in the coming days "in order to draw up political, military and organizational working plans to face the forthcoming phase" in the Middle East.

Such meetings had been foreseen three weeks ago after a meeting of the PLO's 15-member executive committee in Tunis also failed because of internal disagreements to decide on the date and place for the National Council meeting.

The council's endorsement of PLO policies is imperative, especially in view of the current internal debate in the organization over the concept of a "mutual and reciprocal" recognition between the PLO and Israel to open the doors to serious negotiations over the Israeli-occupied territories of the West Bank and Gaza.

The PLO has been under mounting pressure from conservative Arab states such as Saudi Arabia, Morocco, Jordan and Egypt to proclaim its willingness for such a neutral recognition to put pressure on Israel to negotiate and to gain U.S. support for such negotiations.

Disagreement voiced in the discussions here last night and this morning hinged almost directly on this issue, leading some critics on the left of the organization to demand the PLO's outright rejection of the Reagan plan.

Agreement on the date and venue of the National Council has also been hindered by deep differences between Arafat and Syrian President Hafez Assad, whom the PLO leader privately accused of trying to manipulate the PLO for his own national ends.

PLO leaders based in Damascus have insisted that the National Council be held here, as its last two sessions were. Arafat so far has insisted that it be held in Tunis, seat of the Arab League and his own personal headquarters since his evacuation from Beirut. Arafat wants the meeting to be held outside of Syria so that the political independence of its decisions is guaranteed.

Arafat had been expected to meet with Assad during his visit here to try to resolve their disputes. But 48 hours after his arrival -- only his third visit here since leaving Beirut Sept. 2 -- no meeting had materialized.

PLO officials, deeply worried about the two leaders' estrangement, were still lobbying tonight for such a meeting before Arafat's departure, which is expected Saturday.

Arafat plans to visit Jordan after leaving here to hold a new round of talks with King Hussein about some future association between Jordan and a Palestinian state, if such a state is ever achieved.