A top-ranking U.S. disarmament negotiator predicted yesterday that a new nuclear arms treaty with the Soviet Union will not be achieved until next summer.

Until now, the latest date given by U.S. officials was early in 1978. President Carter said two months ago that renewal of the Strategic Arms Limitation Treaty, which expired Oct. 3, would come within a matter of weeks. He later qualified that saying new difficulties had arisen.

In a press conference here, Paul C. Warnke, director of of the U.S. Arms Control and Disarmament Agency, and the alternate leader of the U.S. SALT team, Ralph Earle II, reported progress at the talks but failed to specify its nature.

Earle said he anticipates a new treaty by early summer. "Next spring would be reasonable but by no means certain," he said.

Warnke, saying there also has been progress at the concurrent test-ban talks, described it as "more rapid than I anticipated" because of Soviet President Leonid Brezhnev's proposal last month that a moratorium on peaceful nuclear explosions accompany a ban on military tests.

The two negotiators discussed the state of talks with the Soviets following an announcement that both the SALT and the test-ban negotiations will recess Saturday for Christmas, resuming Jan. 9.