Chancellor Helmut Kohl today rebuffed a confidential plan by the Reagan administration to double the number of Pershing II nuclear missiles scheduled for deployment in West Germany next year, making clear that the Bonn government would accept no more than the 108 Pershing IIs initially called for in the NATO nuclear modernization program.

Reporting to parliament on recent meetings with President Reagan and other Western leaders, Kohl also appeared to caution the United States against rushing preparations for the missiles' deployment. West German officials have objected privately to the U.S. Defense Department about plans to send ground transports for cruise missiles to Britain as early as April, eight months before the nuclear-armed missiles -- also a part of the NATO project -- are to be made operational.

Aside from these two disputes -- which Kohl referred to in just a sentence or two--the chancellor's statement included a long, upbeat account of U.S.-West German relations that he said had become "more solid" since the coalition led by his conservative Christian Democratic Party took power Oct. 1. He noted with pleasure the warm official welcome he received in Washington last week.

Kohl's discussion of the recent change in Soviet leadership was relatively brief. The West German leader emphasized Bonn's interest in continued cooperation with Moscow and said his country would respond positively to Soviet moves toward constructive East-West relations.

"Further developments in Poland will play a role in this, as future Soviet actions in Afghanistan and the behavior of the Soviet Union in the current disarmament negotiations," he said

Stressing that the West desired better relations, Kohl added, "What counts here are actions and facts."

Devoting the main part of his hour-long speech to the NATO missiles plan, Kohl said the West's political will to deploy new medium-range nuclear missiles in Western Europe presented the only chance to persuade the Soviet Union to remove its more than 300 SS20 missiles already targeted on the region.

The 1979 decision by the North Atlantic Treaty Organization calls for the stationing of 108 Pershing II missiles in West Germany and 464 cruise missiles in West Germany, Britain, Italy, and possibly the Netherlands and Belgium, beginning in December 1983 unless a breakthrough in U.S.-Soviet arms-reduction talks makes the deployment unnecessary.

"The medium-range nuclear missiles are the most immediate problem of our security policy," Kohl declared in remarks aimed at the many critics here of the plan. "Those who really want the removal of Soviet SS20 missiles and want to prevent the equivalent rearmament in Europe must support the policy of the NATO double-track decision."

Kohl said he had been impressed in Washington by Reagan's "personal engagement" in the arms-reduction negotiations under way in Geneva.

While avoiding mention of the president's announcement Monday of plans to station 100 intercontinental MX missiles in Wyoming, the Bonn chief welcomed Reagan's accompanying offer to the Soviets of several confidence-building communications measures for nuclear arms control.

At the same time, Kohl asserted that if the stationing of new missiles in Western Europe becomes necessary, "the numbers of systems to be stationed and the timetable for preparations agreed on in the two-track decision holds. Here there is no vagueness."

This statement was an allusion to recent U.S.-West German differences over the details of how to realize the NATO plan. Both the actual number of Pershing II missiles to be deployed in West Germany and the scheduling of preparations for Pershing and cruise missile deployments were the subject of "difficult" discussions during a visit to Washington by Bonn Defense Minister Manfred Woerner prior to Kohl's trip, according to well-informed Bonn sources.

The Germans reportedly charged the Americans with violating the terms of the NATO agreement by planning to station not 108 but at least 216 Pershing IIs in West Germany. The plan was never formally made public. It amounted to two instead of one missile for each Pershing II launcher, which West German sources say was intended as "a massive margin of safety" to ensure that all launchers had spare missiles and would remain fully operational.

But German officials argued that exceeding the initial NATO deployment figure would aggravate public opposition to the missile plan.

A second dispute involved when to ship large, highly visible components for the new missiles from the United States to Europe. The problem was vehicles to be delivered in April for eventual cruise missiles in Britain. Visible preparations for the German-based Pershing IIs are not expected until next autumn.

"What we never wanted was a deployment sequence that would start in April and stretch all through the year," said one Bonn source. "You may argue that sending over unarmed transports has nothing to do with initial operational deployment. But it would create the perception among the public that the deployment had already begun."

West German sources say that "a clear understanding" was reached with U.S. officials not to place more than 108 Pershing IIs in West Germany.