Senate Majority Leader Robert C. Byrd (D-W.Va) cautioned Soviet officials today against suggesting that the U.S. Senate should "rubber stamp" SALT II, saying it would "not contribute to a constructive discussion of the treaty."

Byrd, who will meet Soviet leader Leonid Brezhnev at his Crimean summer retreat Wednesday for a discussion of the new agreement, made his remarks during a Kremlin luncheon.

"I have not come to Moscow to renegotiate this treaty," Byrd told the Soviets. "But any suggestion from a U.S. president or from Soviet officials that the role of the Senate should be that of a rubber stamp would not contribute to a constructive discussion of the treaty."

Byrd's pointed comments on the ratification process, which begins with Senate hearings July 9, came after Brezhney and Soviet Foreign Minister Andrei Gromyko both have bluntly warned the Senate against revising or rejecting the strategic arms limitation pact signed by Brezhnev and President Carter in Vienna, June 18.

Byrd, a key figure in the administration's successful fight for ratification of the Panama Canal treaty, has not yet taken a stand on SALT II, which faces a stiff fight for approval in the Senate, Minority Leader Howard Baker [R-Tenn.] has said he will not favor ratification if the White House and Kremlin will not consider alternations to the pact.

"I have come to Moscow as a representative of the Senate rather than the president," Byrd said in his toast. He came "not to praise nor condemn it, but to examine certain concerns regarding the treaty and to discuss the role of the Senate in the ratification process."

He added that when Carter signed the treaty, "the role of the executive branch. . . .ended and the role of the U.S. Senate to provide its advice and consent formally began."

Upon arrival here this morning Byrd refused to say what he would tell Brehnev. But he remarked that the Soviets "understand very well" the Senate's role.

Both Brezhnev and Gomyko have said that revision or rejection of the treaty, which the Soviets consider the essential ingredient in detente, would threaten superpower stability and deal a severe blow to U.S.-Soviet relations.