A highly combative U.S. information policy overseas to challenge the Soviet Union, Cuba and "Marxist societies" in general is evolving inside the Reagan administration, with one strongly disputed portion of it scheduled for debate today on the Senate floor.

The leaders of the International Communication Agency told Congress during the summer that they intended "to hone the agency into a 'cutting edge' in making America's foreign policy work." Most members of Congress construed that as tolerable hyperbole from a new administration--not a battle cry for across-the-board ideological warfare modeled on the Cold War of the 1950s and early 1960s.

But it is the administration's intent, senior officials now confirm, to sharpen the tone and content of all information disseminated abroad by the United States, while at the same time preserving ICA's credibility.

The core of this burgeoning campaign, which has been surfacing piecemeal, is "Project Truth," authorized in outline by President Reagan and the National Security Council in August.

Additionally, the administration has announced plans to launch a "Radio Free Cuba," known as Radio Marti, separate from the ICA, "to break the Cuban government's control of information in Cuba."

That plan is already opposed by many professional diplomats and others on grounds that include the risk it could expose all American broadcasting to powerful retaliatory jamming.

The issue, scheduled to reappear in the Senate today, is one "cutting edge" of the overall campaign that was never foreshadowed at all, and which administration officials insist was thrust on them by the force of circumstances.

To comply with government-wide budget slashes required by the president's economic restrictions requested in March and again in September, the administration has chosen to make extraordinarily deep cuts in people-to-people exchanges across the East-West divide in the Fulbright Program and the International Visitors Program.

These proposed cuts, already sharply contested in the House, are at stake in 1982 appropriations for the departments of Commerce, Justice, State, the judiciary and other agencies. Instead of complying with administration plans for a 56 percent slash in funds for ICA's educational and cultural programs, a bipartisan group of senators led by Lowell P. Weicker (R-Conn.) would increase those funds by 9 percent, providing $9,139,000 more than the March estimate.

The broader issue at stake is how the United States is portrayed to the world.

To its champions inside the administration, the new hard-hitting information approach is simply giving greater force to the tougher foreign policy mandate that they say Reagan won when he defeated President Carter.

To the opponents, the bristling new campaign is not only ill-conceived but counterproductive, raising the risks of playing into Soviet hands by further alienating the United States from its allies just as a tide of anti-Americanism is sweeping across Western Europe.

The goals of the administration campaign are the refutation of "misleading Soviet propaganda and disinformation" and zeroing in on "the Soviet threat" to world stability and security, coupled with vigorous emphasis on American goals and achievements and the U.S. commitment to peace "from a position of strength."

A current internal memorandum in the U.S. International Communication Agency (USICA), dated Nov. 5, 1981, states that agency Director Charles Z. Wick will direct an interagency committee to coordinate government-wide support for "Project Truth."

The memorandum noted that "a monthly Soviet propaganda alert" is being launched, and plans for "fast response" to all "Soviet disinformation and misinformation" are in the experimental stage, along with special news-features to "highlight positive aspects of the capitalist system" and "the weaknesses of Marxist societies."

To achieve its objectives, the memorandum states:

"Project Truth will use all of the resources currently available to USICA--VOA Voice of America , the wireless file, magazines, films, TV speakers, foreign press centers, international visitors, cultural exchanges, and so on."

No comparable connection between "Project Truth" and all the agency's informational and educational-cultural programs has been previously suggested.

Outcries over the drastic cuts in those programs have come from private and professional groups across the country, and in cables from many U.S. embassies.

Sen. Claiborne Pell (D-R.I.) declared that "having enunciated a policy of reasserting American power in the world, the administration now proposes gutting the single most cost-effective tool of influence in our entire arsenal. Together the Fulbright academic exchanges and the International Visitors Program cost less annually than the production of two fighter aircraft."

Senior officials said in interviews during the past two weeks that they have no desire whatever to curtail these programs, to infringe "to the slightest degree" on the Voice of America's legislative charter for objectivity, which remains "sacrosanct," or "to politicize" any of the agency's operation.

On the contrary, they said, they originally sought to expand all these programs--there are documents showing that--but were obliged to conform to the Reagan administration's multiple budget cutbacks.

Before Reagan took office, nevertheless, Kenneth L. Adelman, a member of his transition team who is now No. 2 U.S. ambassador at the United Nations, publicly described the educational-cultural programs as overfavored by the Carter administration. He forecast that they would be cut back in favor of "the information side" that "has the image of a more confrontational posture . . . . "

Beyond the dispute over any specific program, there are fundamental differences between the administration and its critics over these programs.

The top command in the Reagan administration, and notably the president himself, looks back with nostalgia to the time when there were simple, clear-cut lines in the East-West struggle. Both the Truman and Eisenhower administrations had "truth" programs in those years of Cold War.

To some, those years also bring back memories of the McCarthy era when the U.S. Information Agency and its Voice of America were savaged on grounds they were "soft on communism."

Some of those fears of a "political purge" are recurring among older hands in the Voice, which is one of the most restudied agencies in the government, exposed to the changing policies of each new administration and Congress.

Underfunded and inadequately equipped by modern broadcasting standards, and often battered by political storms, the Voice, in light of the limitations on it, is, nevertheless, well regarded by most professionals for its performance overseas.

The broader concern expressed in Congress and among diplomats and academic specialists about the administration's information policy is over the wisdom of the strategy, and also over the competency of its top appointees to cope with the subtleties of foreign policy and American security.

ICA Director Wick, 64, is an energetic, wealthy California entrepreneur who prides himself on his long friendship with Reagan. He was a political novice until 1979, when he raised millions of dollars in campaign contributions as a "supersalesman" for Reagan.

Wick holds a law degree and a bachelor's of music degree, and was once a music arranger for band leader Tommy Dorsey. His background is in the film, television, theater and publishing areas, and in a profitable chain of nursing homes.

With his flair for publicity, Wick was made co-chairman of the Reagan inaugural ceremonies. He has a family link to House Republican leader Robert H. Michel (Ill.)--his daughter married Michel's son. "Whatever we do will in no way change or skirt the charter of the Voice of America. The greatest weapon we have is the truth . . . to give verifiable truth. The greatest asset that the Voice of America has, and the BBC, is credibility. Without credibility you don't have an audience."

He took office with buoyant hopes for launching a major expansion of the information agency, which the administration intends to rename the United States Information Agency. When those plans collided with the administration's budget cuts, Wick tried in vain to have his agency exempted.

"I'm a team player," Wick said. "I have a dastardly, difficult, painful job" and "we just have to do it better."

Last week, Wick encountered one kind of nationally publicized difficulty that he did not anticipate. In a private briefing he gave on Oct. 23 to the National Council of Community World Affairs Organizations, Wick startled some members of his audience by saying, "We are at war."

As reports of the meeting spread around the country from the 50 participants, Wick, who was on the West Coast last week, told United Press International that he did use those words, but "I meant that we are in a war of ideas with the Soviet Union." Some participants said that was clear to them at the time.

"It's a situation," Wick said, "where we are called warmongers when they are the ones who invade Afghanistan or threaten to invade Poland."

He said he was "absolutely stunned" at the Oct. 23 meeting when a participant alluded to American newspaper reports questioning the accuracy of the administration's "white paper" on El Salvador, published last February. Wick, it was said, responded with "an emotional outburst," and suggested that the question represented the kind of "disinformation" planted by the Soviet Union.

Participants said Wick later apologized for the outburst.

Wick said in earlier discussion with The Washington Post that "yes, we will be more aggressive" in responding to the Soviet Union, for previously "the Soviets have been able to pick and choose their targets."

But in no way, he insisted, will his agency engage in "propaganda." Apprehensions about any change in the "objectivity" of the agency's news product are totally unwarranted, Wick said.

"Whatever we do will in no way change or skirt the charter of the Voice of America . . . . The greatest weapon we have is the truth . . . to give verifiable truth. The greatest asset that the Voice of America has, and the BBC, is credibility. Without credibility you don't have an audience. Therefore, it is of paramount importance that the credibility be maintained."

Any idea that there may be contrary interpretations of what constitutes "basic truth" are dismissed by Wick--and equally by the new chief of the Voice, James B. Conkling, who also has the title of associate director of the parent communications agency.

Conkling, who is 66, has a background much like Wick's, and was Wick's selection for the post. But his amiable, grandfatherly manner is markedly different.

The white-haired Conkling sounded surprised last week to find himself involved in speculation that "a political purge" may be ahead in the Voice of America.

"I didn't ask for this job, and I guarantee you I don't do it perfectly," he said.

Before coming to Washington, Conkling was a director of Bonneville International Corp., which owns radio and television stations. In earlier years he headed a subsidiary that operated commercial short-wave broadcasts beamed to Europe, Latin America and Africa.

Conkling was once a musical arranger for dance orchestras, and even performed on tour with the King family of singers; his wife is one of the King sisters.

He headed Columbia Records from 1951 to 1956, and later founded Warner Bros. Records. From 1975 to 1977, Conkling produced a traveling musical with a patriotic theme, "Threads of Glory."

Conkling said he resented insinuations that he lacked sensitivity in foreign affairs, saying he has traveled and conducted extensive business overseas.

As for speculation that the replacement announced a week ago of the senior career official at the Voice, M. William Haratunian, and another professional may mark the agency's politicization, Conkling said: "Ed Murrow and I sat on the board of CBS, and we were close friends. If anyone accuses me of being a neo-McCarthyite I would really resent it."

Edward R. Murrow, preeminent broadcaster of the World War II and post-war years, who dramatically challenged the late senator Joseph R. McCarthy on television, headed the information agency in the Kennedy administration, at the peak of the agency's prestige.

"We have some 2,200 people" in the agency now, Conkling said, and "the number I am thinking of moving would be a great deal less than I have done at other companies . . . a very minimal number . . . . It won't be a dozen."

It will be Wick and his immediate associates at USICA headquarters who will make basic policy decisions, agency insiders are convinced.

Wick's deputy director is Gilbert A. Robinson, former chairman of his own public relations firm in New York. Robinson served in a variety of government posts in Washington in the 1950s, and prides himself on being the coordinator, as a Commerce Department official, of the American exhibition in Moscow in 1959, scene of the celebrated "kitchen debate" between then-Vice President Nixon and Soviet Premier Nikita S. Khrushchev. That still ranks as the most combative encounter in public between top officials of the two nations.

The agency's chief coordinator for "Project Truth" is Robert John Hughes, better known as John Hughes, who is associate director for programs. Hughes has had a prominent career in journalism as a foreign correspondent, Pulitzer Prize winner, and editor of the Christian Science Monitor until 1979, when he established Hughes Newspapers Inc., in Orleans, Mass.

Robinson said last week that "our efforts to reposition this agency so that we know what the policy is have been more successful than at any time in its history."

The agency, he said, is in consultation with the White House, National Security Council staff, State and Defense departments on a daily basis at high levels.

Hughes said the agency takes "a hard-hitting, but reasoned approach," with "nothing more to offer than the truth." What it is "doing differently," he said, "is reflecting the policy of this administration--which clearly is more assertive than the previous administration."