Chancellor Helmut Kohl and chief U.S. arms negotiator Paul Nitze agreed yesterday on the need for a speedy breakthrough in the Geneva nuclear missile talks, a West German government statement said.

It said the joint West German-U.S. aim at the negotiations was still the complete renunciation by Washington and Moscow of land-based medium-range nuclear weapons.

The statement said Kohl and Nitze, leader of the U.S. team negotiating with the Soviet Union in Geneva, held an extensive discussion on the negotiations to limit medium-range missiles.

"The chancellor and Ambassador Nitze agreed that the object at the negotiations . . . is to achieve a real breakthrough with a concrete negotiating result at the earliest possible time, bearing in mind the firm and valid agreement on the NATO twin-track decision," the statement said.

NATO plans to deploy new U.S. medium-range missiles in West Europe later this year have become a central theme in the heated campaign for the March 6 West German general elections.

Kohl has firmly endorsed the U.S. "zero option" policy to get rid of all medium-range missiles in Europe but his chief right-wing ally, Bavarian Premier Franz Josef Strauss, described it this weekend as nonsensical and unattainable.

A government spokesman sought to play down the remarks and said Strauss had "always been more skeptical" about the proposal but his remarks did not indicate dissension within the conservative parties leading the coalition.

Meanwhile, the opposition Social Democratic candidate for chancellor, Hans Jochen Vogel, unveiled a 14-member shadow cabinet that would form the new government if his party wins the elections.

Although Vogel refused to assign ministries at this stage, he clearly indicated some of his favorites for specific posts. Vogel said Egon Bahr would be the party's main spokesman on all questions about arms control, disarmament and relations with East Germany.