Secretary of State Cyrus R. Vance has reassured Israel that the United States does not intend to change the policy that rules out formal U.S. contacts with the Palestine Liberation Organization, Israeli Ambassador Ephraim Evron said yesterday.

Reassurance that the Carter administration will observe the commitment not to talk to the PLO as long as it does not recognize Israel's right to exist was conveyed during a hour-long meeting the two men had at the State Department late yesterday Evron told reporters after the meeting.

The main topic of the hastily scheduled meeting appeared to have been a continuing dispute between the administration and Israel over an international peacekeeping unit to replace the tunited nations Emergency Force in the Sinai peninsula.

U.N. Security Council authorization for the 4,000-man force expired last Tuesday, and Israel is objecting strongly to a U.S. proposal to replace it with a smaller group of United Nations Truce Supervisory Organization observers to police the Egyptian Israeli peace treaty in the Sinai.

Evron declined to say if he had discussed a possible meeting between Vance and Israeli Foreign Minister Moshe Dayan to resolve the dispute. He did note in passing that Vance had asked for the meeting, a reference that appeared to suggest the United States was putting forward some new thoughts on the disagreement.

The dispute surfaced last Sunday when the Israeli cabinet abruptly rejected the U.S. plan, which had been approved quietly by the Soviet Union. Israeli officials said then that Israel would not present new alternatives but would wait for the United States to come back to its earlier offer to organize a multinational force outside U.S. control to police the Israeli withdrawal from the Sinai.

Dayan, returning to Tel Aviv after a three-day trip to the Netherlands, said that testimony given to a House subcommittee Thursday by Assistant Secretary of State Harold Saunders did not represent a change in U.S. policy. Saunders had described the U.S. approach to getting the PLO to accept Israel and qualify for contacts with the united States as a political rather than a legal problem.

The United States "reaffirmed after the signing of the peace treaty with Egypt that it would continue to refuse to negotiate with the PLO unless that organization accepted U.N. Resolution 242," Dayan said. The resolution, passed after the 1967 Mideast war, calls for the recognition of all the countries in the area.