The Soviet armed forces chief of staff indicated today that the Soviet Union has begun a buildup of strategic nuclear forces to counter U.S. attempts to gain military superiority.

Marshal Nikolai Ogarkov said it had become clear that the Reagan administration intends to pursue an unchecked arms race and that the Soviet armed forces are being developed to deter "aggression."

"In this, special attention is being given to those forces and weapons that ensure the highest degree of the might of the Army and Navy," he said. "The first component of this might . . . is the strategic nuclear forces, which serve as a basic factor to deter an aggressor."

Ogarkov's statement is the most explicit since the Reagan administration took office that Moscow is prepared to match any U.S. developments in the strategic nuclear field. Previous statements from leading Soviet figures have put an emphasis on the need for arms talks rather than emphasizing, as Ogarkov has done, that Moscow is capable of and willing to make its own advancements in the nuclear weapons field.

Ogarkov, who is also first deputy defense minister, made the remarks in an article to be published in the authoritative Communist Party ideological journal Kommunist. Portions of the article were distributed by the Tass news agency before publication.

As the Kremlin's highest ranking career military man, Ogarkov has been closely identified with previous Soviet efforts to advance the SALT process. He participated in the SALT II summit in Vienna involving Soviet leader Leonid Brezhnev and president Carter.

While his remarks distributed by Tass today could be seen as a stiffening of the Soviet position, Western observers cautioned that they also might be a sign of growing Soviet frustration over inability to establish a dialogue with the United States. The Kremlin has shown increasing impatience with what is seen here as U.S. delays in getting new strategic arms talks under way. Secretary of State Alexander M. Haig Jr. said Tuesday in New York that Washington is aiming for the end of this year as a starting point for talks with Moscow.

Moscow's impatience also was reflected in a commentary by the Communist Party newspaper Pravda today that accused the Reagan administration of mounting an unprecedented arms buildup while seeking to obscure its policies with arms control talk.

Ogarkov also accused the Reagan administration of starting the arms race. But he used deterrence to justify Moscow's response only one day after Haig was derided by Tass for making an almost identical argument in his speech in New York.

The preview of Ogarkov's article, according to Western specialists here, did not suggest any changes in Soviet strategic thinking. They said they would have to see the full text before making judgments.

Ogarkov said that neither superpower could achieve superiority, that the Soviet doctrine is defensive and that it envisages "vigorous and up-to-date offensive actions" only if the conflict is forced upon the Soviet Union.

But in a departure from standard Soviet pronouncements on nuclear matters, Ogarkov discussed the catastrophic effects of a nuclear conflict.

"The character of modern weaponry is such that once it is brought into use the whole of mankind would be at stake," he said. The Soviet Union has intercontinental missiles that could strike "with sufficient accuracy" at enemy targets anywhere in the world, he said, and all continents would be drawn into the conflict and the destructiveness could not be compared to any previous war.

A new world war, Ogarkov said, would be "the decisive clash between two antagonistic social systems."

Distribution of the remarks by Tass on its Russian-language service apparently was designed to prepare the population for some sacrifices if both superpowers mount an unrestricted military buildup.

The Soviets are obviously worried about the possibility. They are spending a much higher share of their gross national product on defense than is the United States and the prospect of spending more in a new arms race can hardly be popular here.