In an apparent effort to influence public opinion in West Germany against the planned deployment there of new U.S.-built missiles, East German Communist Party chief Erich Honecker today warned West German Chancellor Helmut Schmidt that "good neighborliness cannot flourish in the shadow of American nuclear missiles."

Honecker's remark, in a luncheon speech during Schmidt's three-day visit here, was a stark reminder of the political stakes in central Europe as Moscow and Washington negotiate in Geneva on the balance of atomic striking power on the continent.

Although the general tone of Honecker's speech was friendly toward West Germany, it seemed clear that he was suggesting that the effort to improve relations -- symbolized by this first intra-German summit meeting in 11 years -- could be held to ransom by the Communist side if the Atlantic Alliance's missile plan goes ahead.

At a joint East-West German press conference later in the day, the East German spokesman, Wolfgang Meyer, expanded on Honecker's public remarks, adding that the East German leader had told Schmidt that a future missile deployment could not help but have an effect on relations and that Schmidt should not tie the fate of his country to those weapons.

In his prepared luncheon remarks, Honecker told Schmidt: "We cannot uncouple ourselves from world politics, but we can, each in his own way, make a substantial contribution to improvement of the international climate" which, he said, had turned sharp and complicated.

In another clear criticism of American plans, Honecker said, "The world does not need long-term rearmament programs, neutron weapons decisions or concepts for limited nuclear wars."

Although Honecker's remarks could influence some West Germans with close family ties to the East, it is not clear what East Germany might have to gain from trying to pressure Schmidt this way, other than to please the Kremlin.

The East German government is highly dependent on a continuing flow of trade, credit and hard Western currency from the Western side of the border.

If the Schmidt government should fall over the missile question, the result could be worse for the East since a more conservative government could come to power and bring the missiles with it.

Schmidt repeatedly has made clear that he supports the allied plan to negotiate with Moscow and to go ahead with plans to deploy the new missiles if those negotiations fail.

The chancellor reiterated that support again today as the two leaders met for the second day of talks at a guesthouse in Doellnsee, a lakeside villa about 35 miles north of East Berlin.

Schmidt said West Europeans view the new triple-warhead Soviet SS20 missiles "with great concern" because they were tipping the balance of power on which stability rests.

The chancellor's spokesman said later that Schmidt does not think the Soviets will push the nuclear button but rather that the Kremlin could use its missile edge for political pressure to intimidate Western Europe.

In his speech, Schmidt described as "honest" the motives behind President Reagan's offer to forego the new missile deployment if the Soviets would agree to dismantle all of more than 600 missiles already deployed and targeted on Western Europe.

"As loyal members of our respective alliances," he said, both German states must bring their historic insight and experience to bear with conviction to find a solution to the current confrontation over atomic arms.

Honecker expressed little optimism over the Geneva talks. He said the fact that they have begun is no guarantee they will produce a good result.

Honecker devoted most of his talk to the "peace" campaign directed at stabilizing the situation in Europe on Soviet terms, which means halting the U.S. missile deployment.

He said that his government will consider with "a sense of good will" all purposeful proposals from the West German side.