AMMAN, JORDAN, FEB. 29 -- Jordan will no longer press for a joint Jordanian-Palestinian delegation to any Middle East peace talks and will support a separate Palestine Liberation Organization seat at the table, sources familiar with King Hussein's thinking said here today.

The Jordanian position, conveyed to reporters accompanying Secretary of State George P. Shultz, seems certain to complicate Shultz's task of finding a basis for peace talks mutually acceptable to Israel and the Arabs.

The PLO already has told Jordan that it no longer has any interest in a joint delegation in the wake of three months of violence in the Israeli-occupied West Bank and Gaza Strip.

Israel has refused to negotiate with the PLO. The U.S. government is forbidden by law to have contacts with PLO representatives until the organization renounces terrorism and recognizes Israel.

U.S. officials have been assuming that any Palestinians participating in new negotiations would be part of a joint delegation with Jordan and would include individuals approved by the PLO.

An aide to Shultz said such a delegation had "always been part of the concept" of a new peace conference and said "it's not an issue." But he would not say whether he thought Jordan would be willing to press the PLO to join a joint delegation.

The Jordanian sources made clear, however, that Hussein is not going to repeat the experience he went through in 1985 and 1986, when he carried out extensive negotiations with PLO Chairman Yasser Arafat on a joint platform and delegation.

While agreement was largely reached on a delegation, the king broke off his negotiations with Arafat in February 1986 because the PLO leader would not make clear his stand on recognizing Israel and renouncing terrorism.

The Jordanian sources made clear today that the Arab position generally has hardened in the wake of the uprising in the occupied territories. They said the Arab world regarded the PLO as the sole legitimate representative of the Palestinian people. In their view, it would be the United Nations, not Jordan, that would issue invitations to a new peace conference.

If the PLO wanted, and could obtain, a separate invitation, Jordan would go along with it, the sources said.

A PLO executive committee member, Mahmoud Abbas, was in Amman in mid-February to reestablish contacts with Hussein but also to tell him that the PLO had no interest in a joint delegation.

The Jordanian sources also made clear that Hussein hopes the United States will find a way to open a dialogue with the PLO. They repeatedly referred to the Palestinians who met with Shultz in Washington Jan. 27 as PLO representatives and suggested those talks should continue.

The two were Hanna Siniora, editor of the East Jerusalem newspaper Al Fajr, and Fayez Abu Rahmeh, head of the Gaza Bar Association. They are known to be strong PLO supporters but are not considered formal members, making it possible for Shultz to see them.

Both were also acceptable to Israel as potential members of a joint Jordanian-Palestinian delegation being discussed in 1985-86 before the Hussein-Arafat talks broke down.

Shultz came here today to answer questions the Jordanians raised about his peace plan during his first visit here Saturday. The Jordanian sources said Amman welcomed Shultz's efforts to revive the peace process.

But they said the Shultz plan needed to be detailed further and a commitment to basic principles of new peace talks agreed to.

Shultz still has not presented any formal plan, although he keeps talking about a "package" that has to be considered as a whole.

His package envisages only a brief "international event" to start the negotiations, hosted by the United States and the Soviet Union rather than all five permanent members of the U.N. Security Council.

An aide to Shultz took issue with the Jordanian description that the Arab position was hardening in the wake of the West Bank and Gaza Strip violence.

He said the Jordanians were "certainly seriously interested" in the U.S. plan, the Egyptians clearly supportive and the Syrians interested in continuing their discussions with Washington.

"I don't see any sign that Arab positions are hardening," he said.

Shultz met the same group of Jordanian officials today that he held talks with Saturday, including Crown Prince Hassan, Prime Minister Zaid Rifai, and Foreign Minister Tahir Masri.

Rifai is scheduled to fly to London tonight to brief King Hussein, who is scheduled to meet Shultz Tuesday in London.