Soviet negotiators in Geneva have made a new proposal on the much-disputed issue of West Germany's Pershing IA missiles, according to U.S. officials, who said it could complicate, but not stop, the final drive toward agreement on a Euromissiles treaty.

State Department spokesman Charles E. Redman said U.S. negotiators are seeking clarification of the Soviet proposal for implementation of an earlier accord about how the West German missiles and their U.S. warheads are to be treated.

White House spokesman Marlin Fitzwater said the Soviet proposal is "not serious in terms of scuttling the whole agreement" on eliminating U.S. and Soviet intermediate- and shorter-range missiles. Fitzwater said that despite the new

dispute, the prospects "are very promising for a treaty and a summit" at which the treaty would be signed.

The 72 West German missiles and their U.S. warheads have been a bone of contention in bargaining on an intermediate-range nuclear force (INF) treaty. The Soviet Union has insisted they be eliminated along with all other weapons of this range, while the United States has insisted that they be excluded from the treaty because they arise from a longstanding "cooperative arrangement" between the United States and a key ally.

A compromise settlement was worked out here in mid-September by Secretary of State George P. Shultz and Foreign Minister Eduard Shevardnadze. Building on West German Chancellor Helmut Kohl's unilateral offer to destroy the Pershing IA missiles when U.S. and Soviet INF weapons are eliminated, the two nuclear superpowers agreed that, in that case, the U.S. warheads that previously had been on the West German missiles would be "subjected to the same elimination procedure and time frame" as other U.S. and Soviet warheads.

The new Soviet proposal, first reported in yesterday's New York Times, is that Moscow be permitted to retain some of its shorter-range missiles until the West German weapons are destroyed. U.S. officials said this proposal was promptly rejected by American negotiators in Geneva.

From the U.S. viewpoint, the Soviet plan would reopen the delicate and recently settled issue of the Pershing IA weapons. An administration official told The Associated Press, "This looks like another short-lived Soviet effort to complicate the negotiations."

Soviet Embassy counselor Sergei Chuvakhin, speaking at an embassy news conference yesterday, described the situation in different terms. Chuvakhin drew a distinction between the question of the U.S. warheads on the West German missiles, which he said had been settled in Washington earlier, and the issue of "the timetable for withdrawal" of the weapons, which he said has not been resolved and is under discussion in Geneva.

Timetable issues, along with procedures for verification of an INF pact, are among the remaining details to be worked out in the Geneva negotiations, which are aimed at resolving all outstanding questions by the time Shultz and Shevardnadze meet in Moscow Oct. 22-23.

Chuvakhin said the timetable questions "are not a big problem" and "should be resolved easily" in the Geneva negotiations. However, he described questions concerning the Pershing IA weapons as "very serious" because they concern "our security and the security of our allies."

Redman said yesterday that, in general, the current round of Geneva negotiations has been "serious and productive on both sides."