West Germany more interested in Easter peace marches than sky lasers

President Reagan's call for a 21st-century missile defense system, including lasers, has gained less attention in West Germany than his proposal to consider deploying fewer medium-range nuclear missiles in Europe later this year.

A spokesman for Chancellor Helmut Kohl summed up the feeling of both government and the opposition by calling the President's proposal ''zukunftsmusik'' - literally, ''music for the future'' but also an idiom for ''castles in the air.''

West Germans are looking seriously at the United States offer to seek something less than the ''zero option'' at the US-Soviet missile talks in Geneva. Mr. Kohl's government hopes the new proposal will help deflate growing opposition to NATO's missile plans and even to membership in NATO itself.

Kohl's coalition of Christian Democrats and Liberals controls a comfortable majority in the new Parliament which assembled today. But this may only accentuate the antinuclear street protests that are to start with more than 90 Easter marches this weekend, and continue through the end of the year.

The Federation of Trade Unions, after officially boycotting such marches, decided this year to join them to prevent the peace groups from being dominated by communist or communist-front groups.

The federation outlined its position during a weekend meeting of trade-union youths in Cologne. Ilse Brusis, a federation executive committee member responsible for youth affairs, told the group that the federation's aim is the removal of all medium-range missiles stationed in or aimed at Western Europe. This meant, she said, that no new missiles must be stationed in Western Europe.

West Germany's opposition Social Democrats, whose position on deployment has not been totally clear, has revealed more of their colors. Horst Ehmke and Oscar la Fontaine, both members of the party's executive committee, spoke out over the weekend against NATO's plan for deploying Pershing II missiles in West Germany if the Soviets and Americans have reached no agreement by late this year to limit their medium-range nuclear missiles.

But the Social Democratic leadership is by no means united on the issue.

Social Democrat Georg Leber, a former minister of defense, and Christian Democrat Alois Mertes, state secretary in the Foreign Ministry, sent a joint letter to the National Conference of Catholic Bishops in the United States. They took issue with that group's proposed pastoral letter, which rejects NATO's policy of using nuclear weapons in Europe if Soviet conventional forces are winning in a war.

Leber and Mertes, while on opposite sides of the political party fence, are both leading Roman Catholic laymen and members of the Central Committee of German Catholics.