House and Senate negotiators broke a longstanding deadlock Thursday and moved to place sharp import curbs on Toshiba Corp. and a subsidiary for selling submarine-silencing equipment to the Soviets.

Approval of the Toshiba provision as part of a sweeping trade bill came despite Reagan administration opposition and a major lobbying campaign by the Japanese electronics manufacturer.On the eve of the action, several Cabinet officials warned lawmakers that a stringent punishment for Toshiba could precipitate a presidential veto of the 1,000-page trade bill. They said the president should have more flexibility in determining national security and trade relations with other countries.

"I was elected as a U.S. senator to represent the state of Utah in the U.S. Senate and not Toshiba and not England and not the State Department and not Frank Carlucci," declared Sen. Jake Garn, R-Utah, in urging lawmakers to defy administration opposition.

He said he was embarrassed that a Republican administration would fight the sanctions, adding, "The State Department has been kicked in the shins and instead of saying ouch they have chosen to surrender.

The provision was accepted by a subcommittee of a House-Senate conference committee working on a compromise version of the trade bill.

It would ban for three years U.S. government procurement of Toshiba Corp. products. The company has massive sales within the United States of televisions, microwaves and other electronic products.

It would ban import for three years of products manufactured by Toshiba Machine Corp., the subsidiary involved with the Norwegian firm of Kongsberg Vapenfabrikk in selling sophisticated computerized milling equipment to the Soviets that the administration says has greatly submarine propeller noise.

There would be exemptions for national security.