Soviets open to banning A-output

President Brezhnev said Wednesday the Soviet Union ''is ready to reach agreement not only on the complete termination of all nuclear weapons tests, but also on ending their further production and on the re-duction and subsequent complete elimination of their stockpiles,'' and offered to speed up US-Soviet nuclear arms reduction talks.

The Kremlin leader was replying to an open letter addressed to him and President Reagan from an Australian organization for international cooperation and disarmament, the official Tass news agency said.

''The Soviet Union is ready for this at any moment, but the American side is incessantly postponing the dialogue on this problem, which worries the whole of mankind,'' he said

Mr. Brezhnev stated that Moscow is ready to ''examine without prejudicd all the proposals of the other side on disarmament. I can assure you that we study carefully the positions and proposals of the other side and never reject them out of hand.''