U.S. and Soviet officials may meet as early as next month to inaugurate an effort to curb the spread of chemical weapons throughout the world, administration officials said yesterday.

A U.S. task force headed by Kenneth L. Adelman, director of the Arms Control and Disarmament Agency, is reported to be in the final phase of internal deliberations before asking the Soviets to set a date and place for discussions to launch the joint effort.

President Reagan and Soviet leader Mikhail Gorbachev agreed at their Nov. 19-21 Geneva summit meeting "to initiate a dialogue on preventing the proliferation of chemical weapons" and to intensify discussions on all aspects of a worldwide ban on chemical weapons, including the question of verification.

The Soviet Union has been considered by administration policy-makers and U.S. intelligence specialists to be at fault in an important part of the worrisome chemical weapons proliferation in recent years.

Adelman said in an interview that "more than 15 nations" are now believed to possess chemical weapons, compared with five nations in the early 1960s. "The proliferation of chemical armaments is gaining momentum," he said. This requires urgent action in both East and West to stop the erosion of the 60-year-old ban on the use of poison gas, he added.

The Soviets are reported by U.S. intelligence to have supplied chemical weapons material, technology or advice to at least six nations listed as having obtained chemical weapons in the past two decades: Egypt, Syria, Libya, Ethiopia, North Korea and Vietnam. If there has been a serious change in Soviet attitudes and policies in this field, said U.S. officials who remain skeptical, it could be of major significance in curbing proliferation.

The Soviets, moreover, have been accused by the Reagan administration of supplying chemical weapons or "yellow rain" toxins for use in Southeast Asia and of using such weapons in Afghanistan. An administration report to Congress Dec. 20, however, said allegations of the use of chemical and toxin weapons in those areas "subsided in 1985." A U.S. official familiar with the intelligence record said reports of use of chemical weapons and toxins in those areas began to decline sharply in early 1983.

Alarmed by Iraq's recent use of poison gas in its war with Iran, officials and chemical specialists from the United States and about a dozen other advanced noncommunist nations, under the leadership of Australia, have held confidential meetings beginning last June to discuss export controls to curb the spread of chemical weapons. One of many problems confronting this effort has been the uncertain attitude of the Soviet Union.

The first sign that the Soviets might be willing to work with the United States in curbing chemical weapons proliferation came from Gorbachev in a speech to French legislators Oct. 3 during his visit to Paris. The Soviets followed up by proposing to the United States in confidential discussions that Reagan and Gorbachev announce in a final summit communique a decision to begin U.S.-Soviet talks on the issue.

The United States, in its draft of the communique, proposed an agreement to work against the spread "and use" of chemical weapons.

In discussions at the summit, the Soviets steadfastly refused to agree to talks about the "use" of chemical weapons -- reportedly at the direction of Gorbachev -- even while agreeing with the United States to work against their spread, according to U.S. officials. Moscow "seemed to be afraid of Soviet-bashing, that we would accuse them on yellow rain and Afghanistan," said an official familiar with the talks.

Despite Soviet refusal to budge on this aspect of the issue, U.S. diplomats said they made it clear they will discuss the "use" as well as the spread of chemical weapons in the talks that are expected to begin soon. Reagan, in a statement of the U.S. position, told a joint session of Congress after flying home from Geneva Nov. 21 that the United States and the Soviet Union "are opening a dialogue on combating the spread and use of chemical weapons."

The hope in the administration is that the forthcoming talks will inaugurate a long-term U.S.-Soviet cooperative relationship on this issue similar to the cooperation between the two superpowers for many years on preventing the spread of nuclear weapons.

Despite a pledge in the Reagan-Gorbachev communique to "accelerate efforts" to obtain a worldwide ban on chemical weapons in the long-running, 40-nation Conference on Disarmament in Geneva, there is little expectation of a breakthrough in this area. An administration priority at the moment is to return to U.S. production of chemical weapons after a 16-year-hiatus as a "deterrent" and bargaining chip with the Soviets.

In an effort to separate the new U.S.-Soviet antiproliferation dialogue from the 40-nation conference, the administration plans to propose that the new meetings take place in Washington, Moscow or a third city other than Geneva.

There is no consensus within the administration about why -- and to what extent -- the Soviets have shifted their positions on proliferation and use of chemical weapons. One line of speculation is that leaders in Moscow, like many other governments, were gravely concerned by Iraq's use of poison gas against Iran, especially because the gas warfare was close to Soviet borders and outside Soviet control.

The latest U.S. estimate is that as many as 5,000 Iranians were killed by Iraqi poison gas in 1984 and 1985. The Iranians, in response, are reported to be combing the world market for chemicals and components to develop a poison gas capability.