MONTEREY, CALIF., NOV. 2 -- Defense ministers of the North Atlantic Treaty Organization gathered here under tight security today to consider plans for deploying new nuclear forces in Europe after U.S. and Soviet leaders sign a treaty eliminating intermediate-range nuclear forces (INF).

The classified plans, drawn up in recent months by NATO's High-Level Group of senior defense officials, are said to include options for deploying new fighter aircraft, battlefield missiles, air-launched cruise missiles and other weapons with nuclear warheads.

These forces fall outside the purview of the INF treaty, which covers U.S. and Soviet medium- and shorter-range nuclear missiles.

A summit meeting between President Reagan and Soviet leader Mikhail Gorbachev to sign an INF treaty is scheduled to begin Dec. 7 in Washington. The "double-zero" treaty would force the Soviets to dismantle their SS20 mobile missiles as well as SS4 silo-based missiles, and SS23 and SS12/22 short-range missiles.

Interest in the new deployments stems from what Defense Secretary Caspar W. Weinberger described as a need to correct the "maldeployment" of nuclear forces that would remain after the INF treaty takes effect.

But senior U.S. and NATO officials have assiduously tried to avoid any impression that the plans to be discussed here this week for the deployment of new nuclear weapons systems are designed specifically to compensate for the withdrawal of 348 U.S. Pershing II and ground-launched cruise missile warheads under the INF treaty.

Such an impression would play into the hands of Moscow, officials said here, by lending credence to recent Soviet allegations that the deployments would enable the West to circumvent the arms agreement.

"As you take down warheads, you have to look at what's left," Weinberger, who is expected to resign soon because of his wife's failing health, told a news conference today. "One of the ways of ensuring that what's left is enough is {through} modernization . . . . This is not to say that we need to bring {different} . . . systems in."

According to an Oct. 22 speech by Weinberger at Johns Hopkins University, one of the new weapons under consideration is "a follow-on to the aging Lance surface-to-surface" missile, which has a range of 74 miles and is deployed in West Germany, Britain, Belgium, Italy, and the Netherlands.

Weinberger also spoke of the need to "increase the effective range" and survivability of NATO aircraft capable of carrying both conventional and nuclear warheads.

"In the absence of the Pershing IIs and ground-launched cruise missiles, this is essential" to provide the alliance with a capability to strike Soviet territory from Western Europe, Weinberger said. The meeting of defense ministers who make up the Nuclear Planning Group takes place twice yearly.

There are 400 U.S. Poseidon submarine missile warheads, 1,071 nuclear-capable aircraft and more than 1,000 tactical nuclear artillery shells outside the INF treaty and available to NATO forces.

A third NATO option, which has aroused some protests from West Germany, is to deploy new battlefield nuclear artillery shells and increase their range from about 12 miles to about 30 miles.

Bonn is said to be concerned that such shells will be used on its territory, and has recommended instead that NATO consider negotiating U.S. and Soviet reductions in such weapons. But other allied governments have opposed the negotiations as a step toward the "denuclearization" of Western Europe.

A fourth option is the deployment of new air-launched cruise missiles with a range of roughly 350 miles. There has also been scattered discussion of deploying new sea-launched cruise missiles under NATO control, but the idea has so far generated little enthusiasm.

A final decision is still months or years away, U.S. Ambassador to NATO Alton G. Keel Jr. said.

Keel acknowledged that the effect of a decision to deploy more modern nuclear forces would be to limit the total number of U.S. warheads removed from Europe, lessening the treaty's impact on NATO's military posture.

He added, however, that none of the options under consideration calls for a "one-for-one substitution" of new warheads for those being removed.

"I think there will be a net reduction" in the number of U.S. warheads under NATO control, Keel said.