As the treason trial of Soviet dissident Anatoly Scharansky began yesterday in Moscow, White House officials branded the proceeding "a sign of weakness" by the Soviet Union and warned that it could affect some aspects of Soviet-American relations.

White House press secretary Jody Powell, reading aprepared statement in response to questions about the Scharansky trial, told reporters:

"It is our view that this sort of repressive action, which strikes at the conscience of the entires world, is a defeat not for those who work for human rights and human dignity, but a defeat and a sign of weakness on the part of those very forces of oppression and injustice which we protest."

Powell's statement contained some of the bluntest language the administration has used to condemn the trials of the dissidents and represented one of the few times American officials have spoken openly of the general souring of American-Soviet relations over the human rights issue.

Both Powell and Secretary of State Cyrus Vance, in separate remarks to reporters, were careful to say that the growing tension over the trials of Scharansky and another Soviet dissident, Alexander Ginzburg, should not impede thestrategic arms limitation (SALT) talks.

Powell, however, said it was now "appropriate" for the United States to reexamine some of its other relations with the Soviet Union.

"This sort of behavior (by the Soviets) does have a negative impact," he said.

Neither the press secretary nor other White House officials were specific on how the trials might affect Soviet-American relations, but they clearly had in mind such things as commercial and scientific contacts between the two nations. To protest the trials, the United States has already canceled plans for a high-levtl scientific delegation to visit Moscow.

Earlier yesterday, a group of Jewish leaders suggested during a meeting with Zbigniew Brzezinski, President Carter's national security adviser, that the United States take other steps to protest the trials.

Stanley H. Lowell, acting chairman of the National Conference on Soviet canceled plans for a high-level scienpathy with the group and said the administration was considering further, unspecified steps in reaction to the trials.

Lowell said the Soviets "take for granted" such things as American technological and economic assistance.

"We can't deal with them on one level where they take and on another level where they kick us in the face," he said.

In his remarks to reporters, Powell predicted that trials would be "self-defeating" for the Soviets and would not silence Carter's human rights criticism of the Soviets.

"If such actions are designed to put an end to those who seek increased human rights within the Soviet Union, they will not do that," Powell said. "If they are meant to stop this president or others in this country from speaking out on human rights in the international community, they will not do that.

"In effect," Powell added, "they will not bury it, but most likely raise it higher."

The trials also sparked protest demonstrations in New York and Washington.

Edward Mezvinsky, the U.S. representative to the United Nations Commission on Human Rights, told about 1,000 people in Manhattan that the president is sending a personal message to Soviet President Leonid Brezhnev expressing his concern over the two dissidents.

Mezvinsky said the message will be carried by Vance to Geneva on Wednesday, when he is to meet with Somyko on progress in the SALT talks.

In washington, about 150 members of the Washington Committee for Soviet Jewry, gathered on 16th Street NW across from the Soviet Embassy. Two of the group sought to enter the embassy but were rebuffed by officials.

Meanwhile, in Jerusalem, Israeli Prime Minister Menachem Begin called for international action to protest the Scharansky trial. "An innocent man's life and freedom . . . are not the internal affairs of any state," he said.

It was also announced yesterday that Scharansky's wife, Avital, will arrive at Dulles airport Wednesday at 3:30 p.m. and hold a press conference there.