North Atlantic Treaty Organization foreign ministers unanimously praised the United States today for consulting its European allies prior to last month's Geneva summit and urged Washington to continue such consultations as it pursues further negotiations with the Soviet Union.

Sources familiar with the secret discussions at the NATO winter meeting here agreed that they were characterized by unusual harmony and praise for President Reagan's performance in his meeting with Soviet leader Mikhail Gorbachev.

The Europeans made clear to Secretary of State George P. Shultz their desire that the United States continue its voluntary compliance with the restraints spelled out in the unratified 1979 SALT II treaty.

There also were signs of continued European uneasiness about Reagan's Strategic Defense Initiative, or "Star Wars," and the effects that the Star Wars research program might have on existing NATO doctrines of nuclear deterrence.

But, the sources agreed, the dominant theme was an upbeat emphasis on what one source called the need for "strength, dialogue and realism" as the United States prepares for further Geneva arms-control talks with the Soviets and an expected second Reagan-Gorbachev summit during 1986.

The ministers also approved a new policy, pushed strongly by the United States, calling for greater efforts to avoid duplication and waste in the development and production of new armaments. NATO officials acknowledged that substantial problems must be overcome if the policy is to be successful, but the U.S. delegation greeted the move as a positive step at a time of "national budget restraints and a widening gap between Warsaw Pact and NATO conventional capabilities."

The major European concern was focused on an impending decision by Reagan about whether the United States will continue adhering to SALT II restraints. Some senior administration officials have advocated abandoning that policy because of alleged Soviet violations of SALT II.

At the time of the last NATO ministerial meeting in June, Reagan announced that the United States would continue observing SALT II restrictions, but would keep reviewing that policy in the light of future Soviet conduct. The sources said that the Europeans, apparently relying on private assurances from Shultz, appear satisfied that the United States will continue that approach.

Some ministers, particularly British Foreign Secretary Geoffrey Howe, reportedly emphasized to Shultz the need for substantive progress in the Geneva arms talks if the United States wants to avoid a resurgence of antinuclear sentiment in West European public opinion.

Others, notably West German Foreign Minister Hans-Dietrich Genscher, reportedly noted lingering concern in Europe that the American SDI program, with its emphasis on a space-based shield against offensive nuclear missiles, could weaken the U.S. commitment to the nuclear defense of Western Europe.

But, while Genscher stressed that considerable further study and discussion is needed about the long-range effects of Star Wars defenses, the sources said that the issue appeared to be less controversial than in the past.