An international congress of intellectuals backed by Poland's communist authorities ended here today with a message supportive of Soviet Bloc policies, but western delegates used its final public session to raise issues of human rights in Poland and call for greater political freedoms.

Polish organizers of the four-day Congress of Intellectuals for a Peaceful Future of the World said about 340 foreign and Polish delegates approved by acclamation a Polish-prepared statement calling for "the elimination of atomic weapons in this century" and "the abandonment of plans for arming outer space," a reference to the U.S. Strategic Defense Initiative opposed by the Soviet Union.

Some western delegates, however, said that they had not been aware of the reference to space arms in the three-page final statement, which was read once aloud to the assembled delgates. Others spoke in favor of Polish political prisoners and the need for "forceful popular movements" in Eastern European countries.

Swedish political scientist Karl E. Birnbaum, the chief of the congress' committee on security issues, reported that the group concluded that East-West stabilization required "the evolution of authentic social forces that have emerged recently both in the East and West," a reference that delegates said was meant to cover Poland's banned Solidarity trade union. "There can be no stable peace without freedom and social justice," the report added.

Norwegian delegate Eva Nordland delivered a speech criticizing Poland's holding of political prisoners and the recent firing of independently elected rectors and deans from state universities. Such actions, she said, created "obstacles to peace."

Although ignored by Poland's state media, the western statements appeared to increase the difficulties of the congress for Polish authorities, who backed the event with funds, extensive publicity and visits by high-level officials but succeeded in winning international attention principally for repression of opposition intellectuals.

The Polish leader, Gen. Wojciech Jaruzelski, recently has had some success in a drive to overcome the economic and diplomatic isolation of his government in the West. But few prominent western intellectuals agreed to participate in the Warsaw conference, and several who came protested the detention on three successive days, beginning Thursday, of opposition leaders Jacek Kuron and Janusz Onyszkiewicz, who had planned to contact delegates independently.

Official disappointment with the congress' results was reflected yesterday in the communist party daily Trybuna Ludu, which objected that western reporters had shown little interest in the congress debates and seemed only "to watch a wall erected by the Polish authorities between the congress and intellectuals of the sort of Jacek Kuron."

Most of the Soviet Bloc delegates and western communists attending the conference dominated discussions with praise for Soviet foreign policies and attacks on the United States, delegates said. About one dozen Americans attended, including four Marxist scholars, the head of a New York-based institute for East-West studies, and members of religious groups.