he Palestine Liberation Organization took what appeared to be a step closer today toward President Reagan's peace plan by publicly listing negotiations for federation with Jordan as part of its proposal for establishing peace in the Middle East.

Outlining the PLO's public position, spokesman Mahmoud Labadi said that four steps were involved, the fourth calling for negotiations on federation with Jordan. Reagan's peace initiative includes support for a self-governing Palestinian entity associated with Jordan.

However, Labadi said that one of the other steps was the establishment of a Palestinian state, which the Reagan initiative opposes, before federation comes about. The two other steps include Israeli withdrawal from the territories it captured in the 1967 war and recognition of the Palestinians' right of self-determination.

Although Labadi insisted that the Palestinians must have their own state first, the seeming flexibility by the PLO on the question of federation was apparently enough to cause concern in neighboring Syria.

Damascus has been openly critical of the talks between PLO Chairman Yasser Arafat and King Hussein that have taken place here over the past three days.

The talks are believed to be centered on the Reagan proposals and ways for the Palestinians and Jordanians to coordinate their responses to it.

Syrian Information Minister Ahmed Iskandar Ahmed was quoted as emphasizing that Arafat on his own could not speak for the PLO in talks with Hussein but needed the mandate of the entire PLO executive committee.

Most members of the executive committee currently are in Amman and have been advising Arafat, so the Syrian statement appeared aimed more at downgrading Arafat than at making a substantive criticism of his authority.

The Syrians have prized their "special" relationship with the PLO -- the organization's official headquarters is in Damascus -- and apparently are unhappy seeing their rival, King Hussein, enjoying reflected glory from improved links with Arafat.

Syria and Jordan have had prickly relations for many years, disagreeing most recently over the Persian Gulf war. Jordan has supported Iraq while Syria backs Iran.

The Syrian statement may also have been designed to signal Arafat that his ability to make concessions is limited by the threat of losing support of pro-Syrian member organizations of the PLO. There have been reports that the Syrians are promoting rivals to Arafat since he indirectly insulted Damascus by choosing to set up his base in Tunis following his evacuation from Beirut.

Different factions in the PLO currently are disputing whether the next meeting of the Palestine National Council, the movement's parliament-in-exile, will be held in Damascus or Tunis.

Labadi spoke to reporters in the courtyard of the PLO center here while Arafat was meeting with local members of the National Council. He said the talks between Arafat and Hussein included discussion of "some kind of federation or confederation" and added: "We are not opposed to any future confederation with Jordan."

He declined to discuss details of the talks, saying, "The cooking is not yet finished."

Labadi repeatedly said that the PLO "hoped that the Reagan plan will be implemented," but, when pressed, he would discuss only the provision in the U.S. initiative providing for Israeli withdrawal from the occupied territories.

The Reagan initiative explicitly ruled out creation of an independent Palestinian state, considered anathema by Israel because of the potential threat to its security.

Labadi indirectly acknowledged the importance to the PLO of obtaining U.S. support, saying "pressure on Israel to withdraw could come only from the United States." Both Reagan's plan and the proposal adopted by the Arab league at Fez, Morocco, last month call for Israeli withdrawal from occupied territories.

But Labadi declined to discuss how the PLO could enlist Washington's support. In particular he declined to say explicitly that the Fez proposal offered Israel recognition of the right to exist within its pre-1967 boundaries. When pressed to define what was the meaning of the relevant clause of the accords, he said only that the Fez statement was a turning point.

Labadi's insistence on establishment of an independent Palestinian state as one step in the peace process and his dodging of questions on recognizing Israel suggested that the PLO is far from openly embracing any position during the talks here that would go beyond the public statement of the PLO's willingness to discuss federation.

Instead, the negotiations between Hussein and Arafat -- aimed in effect at hammering out a joint bargaining position on the occupied territories -- appear at this point likely to yield only some kind of private understanding on steps for the future.

"What is made public at the end is likely to deal in generalities," an Arab editor here said.

Arafat and the Jordanian Prime Minister Modar Badran met tonight on the third day of Arafat's visit. The PLO chairman and Jordan's official news agency Petra both said that the first two rounds of talks with Hussein had been "positive."

This morning Arafat visited Khaw, 27 miles north of Amman, where 265 Palestine Liberation Army fighters evacuated from Beirut are encamped. Referring to the current roundups in Beirut, he accused the Lebanese Army of doing "what the Israeli Army was unable to do."

Arafat said that he had agreed with Hussein that the PLA men should undergo more training, especially in use of heavy arms. "This is our answer to U.S. special envoy Philip Habib and the American-Israeli plot," he said.