Paul Warnke, the chief U.S. arms control negotiator, said yesterday that the United States and the Soviet Union may be able to reach an agreement on a new treaty to limit strategic arms within three months.

In an appearance before the Overseas Writers Club, Warnke said, "We've come more than halfway to the end" of negotiations, "and if we make the same kind of progress in the next three months we can have an agreement."

Warnke also pledged that the United States will not bargain away the North Atlantic Treaty Ogranization's access to the cruise missile in trying to reach a new arms accord with the Soviets.

Apparently seeking to reassure nervous allies and congressional critics that the Soviets will not exact too high a price for a second-stage strategic arms limitation treaty, Warnke said, "for SALT II, I am sure the price is right."

Warnke said the U.S. cruise missile - a pilotless jet that can deliver nuclear warheads with great accuracy - will be covered in a three-year protocol to be attached to the new treaty.

Reports based on leaks from congressional arms experts have said the United States has agreed to suspend development of the cruise missile's intercontinental version for three years in return for comparable Soviet concessions. It will reportedly continue development of shorter-range cruise missiles, which are of special interest to the European allies.

Although he declined to say so directly, Warnke appeared to confirm those reports in his answers to questions.

The West Germans and the French have expressed an interest in obtaining various versions of the weapon, while the Soviets want U.S. agreement to prohibit the transfer of cruise missile technology to other nations.

Referring to "apprehensions on the part of the NATO allies" on that score, Warnke said, "In any agreement, it is necessary that we protect our options. Those options will be preserved." Our allies, he said, "recognize that you accept restrictions on arms that could be useful to us, in order to obtain military restrictions on the other side."

Warnke also said "I don't necessarily take seriously" Soviet President Leonid I. Brezhnev's threat to develop a neutron bomb if the United States produces such a weapon.

Warnke said the neutron warhead, intended for use in Lance missiles and artillery, is designed to defend against massive tank attacks.

He suggested the Russians are not serious about developing such a weapon because, with a roughly 2 to 1 edge over NATO forces in tanks, they are not worried about an armored attack being launched against them or their allies from Western Europe.

The neutron weapon, according to its brackets, would destroy tank crews with intensified lethal radiation without causing heavy blast and fire damage in the general area, thus restricting the loss of civilian life.

"It kills more Russians and fewer Germans," Warnke said. "That is really what the neutron bomb is designed to do - to defend against a Soviet tank attack."

Warnke said that what he called a "Soviet propaganda campaign" against the neutron bomb will not decide the issue of whether the United States produces the weapon. President Carter has promised a decision on this after he gets the views of allies in Europe where the weapon would be used in event of war.