Defense Secretary Caspar W. Weinberger said yesterday that the current West German spy scandal does not shake U.S. trust in European allies or alter plans to include them in sensitive research on the proposed Strategic Defense Initiative.

"Espionage is a very unfortunate act wherever it occurs, and we'll do our best to guard against it, but we aren't going to say that because there has been espionage in Europe that we therefore can't trust Europe with anything," Weinberger told reporters from North Atlantic Treaty Organization countries.

His remarks came amid a major espionage controversy in Bonn highlighted by the defection to East Germany of one of West Germany's leading counterintelligence officers and the arrest of a secretary in the president's office.

The Reagan administration has invited NATO allies to cooperate in research on the SDI missile-defense system, and a top-level West German delegation arrived here last week for talks to determine whether Bonn participates.

The NATO journalists, who met Weinberger at the Pentagon, questioned him most frequently about the SDI, reflecting the debate in Europe about the scope and intent of the U.S. invitation on research.

Asked about potential security leaks posed by such technological partnership with European nations, Weinberger noted that the Soviet Union is "quite avaricious as far as acquiring technology the easy way."

He said, however, that precautions could be included in agreements with European governments and firms to prevent security breaches because "it's to nobody's interest, ours or any other friendly country," that such problems occur.

Japan and several European nations, including Great Britain, Italy and West Germany, have sent representatives here to discuss SDI work, he said, and he predicted agreement with London "quite shortly."

Weinberger responded to many of the fears expressed by the allies, emphasizing at one point that the United States is seeking "contributions of the mind" from Europe, not financial contributions for the estimated $26 billion research effort.

He also said SDI partnerships will not cause a "brain drain" from Europe to the United States and will not rule out commercial application of the research by European firms.

"What we're interested in is getting a maximum number of people to work on this project, which we think is a very noble goal which offers really more hope to the world than anything else," Weinberger said of the system intended to shoot down enemy missiles before they can hit targets in the United States.

He repeated assurances that deployment of such a nuclear umbrella would not "decouple" the United States from the defense of Europe.