The Soviet Union will restore ties with Israel if it attends an international Middle East peace conference and starts talks with the PLO, Soviet Foreign Minister Eduard Shevardnadze said Thursday.

Once Israel stopped rejecting a conference and dialogue with the PLO, "our two countries could take yet another step toward re-establishing full diplomatic relations, and the beginning of the conference would be a starting point for resumed relations," he told a news conference.Shevardnadze was speaking after separate meetings on Wednesday with PLO Chairman Yasser Arafat and Israeli Foreign Minister Moshe Arens. Arens flatly rejected a call for direct talks with the Palestine Liberation Organization.

The Soviet foreign minister's talks with leaders of the Middle East's two main adversaries marked the high point of a 10-day peace campaign in which Arab states have supported Moscow's call for international peace talks under United Nations auspices.

His meeting with Arens was the highest-level formal Soviet contact with Israel since the Kremlin cut relations during the 1967 Middle East war in which Israel crushed the Soviet Union's Arab allies.

In a statement at his news conference, Shevardnadze said the idea of an international conference was not welcome to Israel.

"But our view is that the conference would indeed give a chance for a historic compromise between the Arabs and the Israelis."

Moscow would try to overcome differences between Arab states so that they would take part in a peace dialogue, he said, calling for talks between leaders of Syria, Egypt, Jordan, the PLO and Lebanon "to speed up the convening of an international conference."

Syria, Moscow's chief Arab ally, and Egypt, the only Arab state pledged to peace with Israel, have no formal relations.

Shevardnadze called for a deadline of six to nine months for intensive consultations between the big powers and the parties involved in the Middle East conflict - through mediators if necessary - to prepare for an international conference.

In Moscow's fullest explanation of its formula for peace talks, Shevardnadze said an international conference under U.N. sponsorship would serve as a "collective mediator" and "a kind of safety net to guarantee the negotiations from failures."

Two issues needed resolving - the conference's political and legal basis and Palestinian participation, he said. The rest could be decided at the conference.