The Kremlin is more confident now than at any time since the Carter administration took office in 1977 that a new strategic arms limitation agreement soon will be reached with the United States, but the leadership is hedging on where a SALT II summit should be held.

This is the message of President Leonid Brezhnev's policy address yesterday, in the view of Western analysts here. In his speech, Brezhnev virtually brushed aside such bilateral problems as Chinese-American rapprochement, and spoke in detailed, optimistic terms of the likelihood of a SALT agreement in the near future. He said it probably will have a positive effect on other complex arms issues, such as a comprehensive test ban, force reductions in Europe and conventional arms sales by the great powers.

But in speaking of a future signing ceremony with President Carter, Brezhnev used the Russian word for "meeting," instead of the word for "visit." He declared that "when its drafting is completed, the new agreement will probably be signed during my meeting with President Carter, hopefully in the near future."

Observers here believe the choice of the word "meeting" was deliberate by Brezhnev. Early last month, Soviet sources began hinting unofficially in Washington that Carter should come here for the signing, and Brezhnev may have indicated yesterday that Moscow -- or perhaps a third country, such as Switzerland -- may be a better place than Washington for a summit.

In the past decade, American presidents have journeyed three times to the Soviet Union for summits with Brezhnev, and he has traveled once to Washington -- in June 1973. President Nixon came here in 1972 and 1974 and President Ford met Brezhnev in the Soviet Pacific port city of Vladivostok in November 1974. Ford met Brezhnev again in Helsinki in the summer of 1975 for the signing of the Helsinki accord on European security and cooperation.

The Kremlin is among the most protocol and status-conscious governments in the world, and in this arcane area of international diplomacy, who visits whom and where is accorded enormous significance. Too many knocks at the Kremlin door by American presidents could have the effect of making the United States appear the petitioner, and thus in a weaker position. Lest such an impression creep into Soviet perceptions of its relations with Washington, American diplomats here are known to have advised the State Department that it is time for Brezhnev to go to Washington.

However, Brezhnev at 72 is far from being a healthy, vigorous man. He is thought to have suffered a stroke some years ago and his speech yesterday was slurred as it has been in recent years. He paused and stopped at odd moments during his address, like a man who might not be following the sense of what he was saying.

It is commonly believed among foreigners here that the circle of personal aides Brezhnev has collected in the past few years screens out all but the most pressing work for their aging boss, who is both head of state as president and political chief as Communist Party general secretary. Brezhnev takes long summer vacations and reportedly only returned to Moscow last week after a month's rest on the Black Sea.

Most Westerners who have met with him in recent months have said the sessions are largely confined to reading prepared statements on both sides, with little spontaneous ad libbing. The Soviets seemingly are not eager to expose their leader, who walks slowly and with a distinct limp, to comparisons with 74-year-old Chinese Vice Premier Teng Hsiao-ping, who appeared vigorous and spry during his recent American visit.

One gauge of Brezhnev's present vitality will come at the end of the month, when French President Valery Giscard D'Estaing pays a state visit here. French diplomats expect that the two leaders will engage in open discussion. But the French are the sources of reports in the summer of 1977 after a Brezhnev visit to Paris that the Soviet leader's health was ebbing quickly.

Western analysts here, some of whom carefully videotape each of Brezhnev's televised appearances, say his vitality rises and falls in abrupt curves.

That instability is bringing a time of transition ever closer to the leadership and the Soviets may have substantial reasons for shying away from an exhausting journey to Washington for Brezhenev.