Former secretary of state Henry A. Kissinger urged the Senate yesterday to approve the U.S.-Soviet treaty to eliminate Intermediate-Range Nuclear Forces (INF) but expressed "grave reservations" about its likely effect on the East-West balance of power.

"Failure to ratify the treaty or insistence on amendments requiring renegotiation would not cure its defects," Kissinger told the Senate Foreign Relations Committee. "It would, on the contrary, vastly magnify all difficulties."

Senate rejection of the treaty at this point would "generate a crisis in the Atlantic Alliance which would in the end almost certainly lead to the unilateral withdrawal of U.S. missiles from Europe and undermine the cohesion of the alliance," he said.

Moreover, Kissinger contended, confidence in U.S. leadership would be "severely undermined" and neutralist sentiment would grow. "The Soviet strategy of dividing the Atlantic Alliance would be greatly enhanced."

But he expressed fear that the treaty would reduce U.S. ability to retaliate with nuclear weapons based in Europe against Soviet aggression while also failing to significantly reduce the Soviet nuclear threat to Europe.

By forcing NATO to rely on U.S. weapons in more distant locations for nuclear deterrence, he said, the treaty creates a "psychological and political imbalance which is greatly magnified by Soviet superiority in conventional forces."

While the Senate cannot afford now to block the treaty, it should insist in the future on moves to reduce the imbalance of conventional forces in Europe as well as curbs on Soviet activities elsewhere, including Africa and Central America, he said.

He also said INF verification procedures are inadequate for other arms accords.

Meanwhile, chief INF negotiator Maynard W. Glitman told the Senate Armed Services Committee that the treaty would not impede U.S. efforts to help NATO modernize its remaining nuclear arsenal, despite contrary Soviet claims.

And committee chairman Sam Nunn (D-Ga.) tried anew to put a constitutional roadblock in the way of administration attempts to reinterpret the 1972 Antiballistic Missile (ABM) Treaty.

Nunn on Monday noted assurances from Secretary of State George P. Shultz that testimony such as Glitman's would constitute an authoritative interpretation of the treaty.

Such INF pact constitutional assurances should apply to other treaties, said Nunn, who contends that Nixon administration testimony during ABM ratification requires a narrow treaty reading that precludes advanced testing of space-based missile defenses.

The White House and conservative Republicans say that Shultz' assurances do not apply to the ABM dispute.

But, Nunn said, "I do not happen to agree . . . that Secretary Shultz's letter pertains only to the INF Treaty and has no bearing on the administration's responsibility with regard to past or future treaties."