Soviet leader Yuri Andropov said tonight that his government was "prepared to facilitate" the creation of a nuclear weapons-free zone in Northern Europe and offered to discuss turning the Baltic Sea into an area free of nuclear arms.

In a speech honoring visiting Finnish President Mauno Koivisto, Andropov added a new element to an old proposal for a nuclear weapons-free Nordic area by voicing readiness to negotiate a pledge to keep Soviet nuclear-armed submarines out of the Baltic.

Although the proposal was vague, it suggested that Moscow was prepared to negotiate the presence of at least six Soviet nuclear-armed submarines in the Baltic Sea for as yet unclear political concessions. The statement, however, did not imply that Soviet nuclear subs could not transit from Soviet Baltic ports to the Atlantic.

The proposal appeared to have a propaganda value, particularly after the October 1981 incident in which Swedish experts detected nuclear arms on board a Soviet submarine stranded near Sweden's Muskoe naval base. Subsequent detection of submarines believed to be of Soviet origin in Swedish and Norwegian coastal waters has damaged Soviet credibility further in Scandinavian countries.

The 1981 incident involving Soviet submarines has led western military specialists to believe that Moscow has more than six nuclear-armed submarines stationed in the Baltic Sea.

In his Kremlin dinner speech, Andropov took account of criticism that the earlier Soviet proposals for the creation of a nuclear weapons-free zone in Northern Europe did not include Soviet territory adjacent to Norway and Finland.

"We would," Andropov said, "not only assume a commitment to respect the status of such a zone but would also be ready to study the question of some measures, and substantial measures at that, concerning our own territory adjoining the zone, which would enhance the consolidation of its nuclear-free status.

"The Soviet Union also could discuss with the interested sides the question of giving nuclear-free status to the Baltic Sea."

The Soviet leader reiterated an earlier warning that the deployment in Western Europe of new U.S. nuclear missiles would provoke Soviet countermeasures both against the United States as well as against the five European countries where these missiles are due to be placed.

"We would not want matters to go that far," he said, adding that Moscow wanted to reach an agreement with the United States on limiting strategic arms provided that it was "an honest and equal" pact.

The speech by Andropov highlighted the first day of Koivisto's five-day visit to Moscow and came after the two nations agreed to extend for another 20 years the Soviet-Finnish treaty of friendship, cooperation and mutual assistance.

The pact recognizes the two countries' post-World War II border and has allowed for substantial trade between the two countries and reasonably cordial political relations.