GENEVA, NOV. 22 -- Secretary of State George P. Shultz said today the United States will offer the Soviet Union on-site inspection rights at a U.S. missile facility as part of an effort to strike the final bargain Monday and Tuesday on an arms control treaty to be signed at the Washington summit conference.

Speaking to reporters during his flight here for wrap-up meetings with Soviet Foreign Minister Eduard Shevardnadze, Shultz said the negotiators on both sides appear to be coming to the showdown sessions with both the intention and the authority to resolve remaining issues in the way of completion of the intermediate-range nuclear forces (INF) treaty.

"We expect and they expect to have the treaty concluded so it can be signed at the summit meeting," which is scheduled to bring Soviet leader Mikhail Gorbachev to Washington Dec. 7, said Shultz. "That's an essential ingredient, and we'll finish it," he said.

Shevardnadze arrived in Geneva shortly before Shultz and said he "thinks and expects" that the treaty can be concluded for signing at the summit. However, he cautioned that "difficult {and} very sensitive issues" remain to be decided in the next two days.

Shultz and members of his delegation, which includes President Reagan's newly chosen national security adviser, Lt. Gen. Colin Powell, were encouraged by the promised presence here of Marshal Sergei Akhromeyev, chief of staff of the Soviet armed forces and a figure of great authority.

Shultz said Soviet officials informed him in recent days that Akhromeyev will be in their delegation, telling him "you should see from that that we intend to finish" the treaty. U.S. negotiators have noted in the past that much more progress on detailed arms issues is made when Akhromeyev is present.

The inspection rights that Shultz said he will offer the Soviets are in return for a precedent-setting Soviet agreement last week to permit U.S. inspection of the Soviet assembly facility for SS25 long-range nuclear missiles.

The SS25 is not covered by the treaty banning medium-range and shorter-range missiles. But it is difficult to distinguish from the less powerful SS20 missile, which is covered. The United States has demanded the right to station inspectors at the Soviet SS25 facility for 13 years to make sure it does not continue to turn out SS20 missiles once they are banned, and the Soviets demanded the right in return to station inspectors at a U.S. plant "of comparable value."

"We have to recognize that just as we want to see what's going on there {in the Soviet Union}, they want to see what's going on here {in the United States}. That's fair enough," said Shultz.

He said the administration has approved an offer that it believes the Soviets will accept. He would give no details other than to say it involves observation of the production of a missile or key component, but other officials said the U.S. offer is for Soviet long-term inspection of a ballistic missile facility that was included on a recent list of inspection sites of interest presented by Moscow.

The Soviets originally insisted on inspecting the General Dynamics plant in San Diego that builds both ground-launched and sea-launched cruise missiles. The two models are nearly identical, but only ground-launched missiles are covered by the INF treaty. The United States rejected this proposal because of the military secrets involved.

While appearing confident that a compromise can be worked out, some officials traveling with Shultz were uncertain that the Soviets will quickly accept the U.S. proposal.

Shultz indicated that inspection and verification issues are foremost among those remaining to be settled, and that all the remaining issues would have been considered only "a detail" from the vantage point of the negotiations as they stood this spring.

The verification arrangements already concluded for INF "go far beyond anything ever contemplated in earlier treaties," said Shultz, ticking off elements that both sides have approved. He said these include the right of inspectors to go to "sensitive places," procedures on how they will get there, the frequency of inspections and the time period for inspections -- the three years in which the medium-range missiles are being eliminated and a 10-year verification period after that.

Nevertheless, he added, "some aspects of operational detail" are still to be worked out in the meetings Monday and Tuesday.

In projecting last-minute decisions to wrap up the treaty negotiations, Shultz rebuffed the views of the Pentagon's departing chief arms control official, Frank J. Gaffney Jr., who said Friday that "a dangerous situation" has been created because of the requirement to negotiate against the summit deadline.

"Having time pressure and a deadline is a good thing. Without a deadline it's almost impossible" to get decisions made on complex issues, Shultz said. He added that "we don't have any intentions" of accepting essentially disadvantageous positions just because a deadline is near.

Beyond INF, Shultz said he intends to work with Shevardnadze on a broad range of other issues in preparation for the Reagan-Gorbachev summit. These include:

A strategic arms treaty. Shultz said "it is possible" to negotiate such a far-reaching pact and ratify it in 1988 and therefore it is very important that "we should do everything we can" in this effort. A strategic arms pact, including some accord on the status of antimissile activities such as Reagan's Strategic Defense Initiative, is expected to be the most important and probably the most contentious issue for Reagan and Gorbachev next month.

A Soviet withdrawal from Afghanistan. Shultz said U.S.-Soviet discussions on this issue have been "increasingly frank and realistic." He suggested that the United States might accept the lower end of a troop withdrawal timetable, of seven to 12 months, publicly discussed by a Soviet official last week.

Shultz said that a transitional regime to govern Afghanistan after a Soviet withdrawal cannot be built on the present Soviet-backed Afghan government in Kabul, "which does not represent in any way the Afghan people generally."

He said announcement of a Soviet withdrawal timetable should come before work on a transitional government for a neutral, nonaligned Afghanistan and pledged that, under this sequence, the United States "will work to help create that sort of situation."

The Persian Gulf. Shultz again expressed frustration with Iran's unwillingness to accept a U.N.-mediated peace and said the time is approaching when the Soviets will have to decide whether to back a U.N. arms embargo against Iran.

Gorbachev's schedule in Washington. Following the collapse of a plan for Gorbachev to address a joint meeting of Congress, Shultz said it is important for Gorbachev to have "conversational-type contact" with members of both houses of Congress, and especially with senators from key committees that will have a role in ratification of the INF pact once it is signed.

Shultz expressed confidence that this sort of contact between Congress and the Soviet leader can be worked out.

Human rights. Shultz said that "we've seen considerable progress" in this area but that it is "still very far from being a satisfactory situation."