The main society of American physicists said yesterday that both the United States and Soviet Union have "more than" enough nuclear weapons, and that adding more to their arsenals will not help protect either.

In effect, the American Physical Society, which includes the scientists who developed the A-bomb and some who now make H-bombs, came close to joining the nuclear freeze movement.

It called on both nations "to intensify substantially and without precondition" efforts to limit the number and deployment of all nuclear weapons and to halt nuclear testing "in all environments for all time."

"The nuclear arsensal of both the United States and the Soviet Union are more than adequate for deterrent," the society said in a statement, adding, "Continuation of the arms race will not increase the security of either superpower."

The statement--based on a resolution passed Jan. 24 by the society's council--was written by five leading physicists: Hans Bethe of Cornell, one of the World War II architects of the A-bomb; Herbert York, a former director of Defense Department research and engineering; Sidney Drill and Wolfgang Panofsky of Stanford, and Marvin Goldberger, president of California Institute of Technology.

Physicists are the principal scientists who developed the A-bomb and then, even before World War II ended, began efforts to curb its future use.

Despite all such efforts, the society conceded, nuclear war has become "an unprecedented threat to humanity," one that "could destroy civilization."

Nuclear freeze advocates have called for bilateral negotiations to halt production, testing and deployment of nuclear weapons. The recommendations of the physicists, some of whom still work in the nation's weapons laboratories, were only slightly less sweeping.

They called on President Reagan, Congress and Soviet leaders to negotiate seriously and urgently to achieve "equitable and verifiable agreement" to "reduce significantly the number of strategic weapons and delivery systems . . . to restrict the use and limit the deployment of battlefield and intermediate-range nuclear weapons . . . to prevent the spread of such weapons to outer space" and to ban all testing.