U.S. economic sanctions against Nicaragua were greeted today by widespread disapproval from other participants in the Bonn summit of industrialized nations. They warned that the sanctions are likely to drive the leftist Sandinista government even closer to the Soviet Union and Cuba.

The United States avoided formal protests against the sanctions imposed Wednesday by not asking for any endorsements. Secretary of State George P. Shultz and White House chief of staff Donald T. Regan acknowledged, however, that the sanctions are not popular with European nations or Canada.

"They were not satisfied with our course of conduct, but it was something we felt we had to do," Regan said.

Shultz, even while supporting the sanctions, indicated some reservations about them. He did not respond directly to a question about whether he had argued against imposing sanctions, but another administration official said that "the secretary's reservations about sanctions are well known."

West German Foreign Minister Hans-Dietrich Genscher said that the four European participants in the seven-nation summit do not believe in trade sanctions as an effective instrument of foreign policy.

"It is well known that European states do not tend toward embargo measures in any form," Genscher said.

Some of the sharpest criticism of the sanctions came from Canadian Foreign Minister Joe Clark, who received assurances from Shultz that the United States would not interfere with Nicaraguan-Canadian trade. But Clark said that Canada would monitor this trade anyway, to make certain that Canadian subsidiaries of U.S. companies are not affected by the embargo decision.

"I think we should have been notified," Clark said. "Neither we nor our allies were notified."

The storm of protest against the sanctions broke at this afternoon's meeting of foreign ministers, where representatives of other nations consider Shultz to be more sympathetic to their position than President Reagan is.

British Foreign Secretary Geoffrey Howe and French Foreign Minister Roland Dumas warned that sanctions would drive the Sandinistas closer to the Soviets.

A similar point was made by Italian Foreign Minister Giulio Andreotti, speaking on behalf of the 10-nation European Community, who denounced the sanctions as an "ineffective measure."

At a press briefing this afternoon, Shultz was asked about a statement attributed to Senate Foreign Relations Committee Chairman Richard Lugar (R-Ind.), who was quoted by a reporter as saying that Shultz had opposed the sanctions.

Shultz ducked the question, saying that "the trade embargo has been imposed" and that it was "a timely thing to do." He then said he was opposed to breaking off diplomatic relations with Managua and called for "a negotiated end to the violence and instability in Central America."

Later in the briefing Shultz said that neither the Europeans nor the Canadians see sanctions as "a good tool to use for foreign policy purposes."

He also appeared to make the case against sanctions that some officials say had been his position within the administration before they were imposed.

Shultz said that economic sanctions "can have a considerable impact if they are generalized," meaning that several nations or the providers of a given vital commodity agree to impose them. The embargo against Nicaragua was "much more limited than if it were generalized," he added.

As a general rule, Shultz said, "I think the idea of sort of diddling around with trade to cause somebody to make some adjustment in their foreign policy of one sort or another is something that you should only do in very special cases."

In announcing the imposition of the sanctions Thursday, White House spokesman Larry Speakes said they were "in response to the emergency situation created by the Nicaraguan government's aggressive activities in Central America."

Speakes has been asked at every subsequent briefing to name a country that supports the sanctions. He has not named one.

The sanctions imposed a total embargo on trade, suspended U.S. landing rights for Nicaraguan planes and ships and terminated a U.S. treaty of friendship, commerce and navigation with Nicaragua.