The United States should move beyond doomsday nuclear weapons and field more non-nuclear ones with pinpoint accuracy, which could be fired in regional conflicts in the Third World and elsewhere without triggering all-out war between the superpowers, a blue ribbon advisory commission states in a report to be presented to President Reagan this week.

"Threatening a nuclear exchange that would devastate both the Soviet Union and the United States is not a reliable deterrent" to would-be aggressors in Third World hot spots far from Europe where NATO and Warsaw Pact forces have confronted each other for decades, the commission contends in calling for a more diverse national arsenal.

A bigger assortment of precision conventional weapons, along with stealth aircraft and missiles that are difficult to detect electronically, would also bolster NATO's "counteroffensive" capability against the second and third echelons of Warsaw Pact forces, according to the commission.

The advisory panel's report, obtained by The Washington Post from sources who placed no embargo on its release, stops short of endorsing Reagan's Strategic Defense Initiative specifically. But it recommends "pushing to deploy defensive {missile} systems even if their value is at first limited," and decries that the SDI debate has focused "on the degree of perfection attainable."

The 13 commissioners, who include former secretary of state Henry A. Kissinger, former presidential national security advisers Zbigniew Brzezinski and William P. Clark, two retired generals and an admiral, also agreed there may not be enough money to pay for all the ships, aircraft and missiles the Pentagon plans to buy, forcing tough choices.

"Smart" weapons, of pinpoint accuracy, should be favored over "large platforms {ships, aircraft}" in any future budget crunches. The panel's call for reordering defense priorities echoes those made to Reagan six years ago by several administration officials.

In 1982, Frank C. Carlucci, then deputy defense secretary and now defense secretary, ordered an investigation, including lie detector tests, when The Post printed excerpts from a secret Pentagon briefing by two senior officials warning of a $750 billion shortfall in the Reagan rearmament program. A new estimate, prepared by the System Planning Corp. but not included in the commission's report, warns that the shortfall could be $3.6 trillion by 2010 if today's Pentagon buying plans are not radically changed.

Brzezinski told The Post that if the commission's report "produces a greater degree of prioritization," it will be worth its $1.6 million cost.

But some commissioners disagree over the meaning of a key panel recommendation that costly combat ships and warplanes be sacrificed in any Pentagon budget crunch for advanced non-nuclear munitions and battlefield equipment. There also have been complaints from Congress and elsewhere about the makeup and operations of the panel.

If the Pentagon runs short of money, the report states, "it would be better to protect continued growth in advanced non-nuclear munitions, conventionally armed tactical missiles, sensors and communications systems while taking cuts in the large platforms {ships, aircraft} and other elements of our force structure."

A civilian commissioner told The Post this means fewer aircraft carriers and B1 bombers should be bought, to free money for smart weapons. But another commissioner, a flag officer, disputed this, saying it means the Air Force and Navy could postpone developing new stealth fighters to free money for precision weaponry. Under this interpretation, Air Force F15 and Navy F14 fighters would be kept flying longer than now planned.

The Senate Governmental Affairs Committee has asked the General Accounting Office (GAO) to investigate allegations that the commission spent its money lavishly, that its membership does not provide the balance of viewpoints required by law and that there were conflicts of interest in parceling out work to contractors.

Pentagon officials denied the allegations, saying that the commission spent $1.6 million of its $1.7 million budget in preparing the 69-page report. This works out to more than $20,000 a page, one critic noted. A Pentagon official said its lawyers were careful to avoid conflicts of interest in preparing the report and followed rules of the Federal Advisory Committee Act covering such panels.

Then-Secretary of Defense Caspar W. Weinberger and then-national security adviser John M. Poindexter in October 1986 established the Commission on Long Term Strategy to study what kinds of offensive and defensive forces the United States would need most between now and the year 2010. Cochairmen are Fred C. Ikle, under secretary of defense for policy, and Albert Wohlstetter, director of research at Pan Hueristics, a California firm specializing in defense issues that did considerable work for the commission.

Wohlstetter, Brzezinski and several other commissioners and staff members said the panel made an important contribution by reaching consensus and making a case for restructuring U.S. offensive and defensive forces for the next 20 years.

One commissioner conceded no radically new concepts are set forth, declaring, "If I had to make a lecture on what is new in here, I'd be out of words in five minutes. But you have big shots from different administrations saying it. That's what is new."

The report states that while U.S. forces in Europe and South Korea, backed by the threat to use nuclear weapons, have kept the peace there for decades, "Soviet power has bypassed the lines we drew and has pushed into southern Asia, the Middle East, Africa, the Caribbean and Central America. In a world less polar than it once was, the strategy has not helped much in dealing with hostile countries (Iran, for example) outside the Soviet bloc."

To gain more leverage in the Third World, the report states, the United States should make more use of satellites and reconnaissance drones to determine for itself and friendly governments what rebel forces are doing. Retired Army general Paul Gorman, one of the commission's consultants paid between $50,000 and $100,000 for advice, championed this approach while head of Southern Command, which oversees U.S. military activities in Latin America.

The commission warned that the Soviets could seize the Persian Gulf unless the United States and its allies strengthen military capabilities in the region. "Building up Turkey's defense capabilities, particularly those for air defense, would cast a strong shadow over any Soviet planning for operations in the gulf region," the report said. "The threat we will face in the region is that the Soviet Union will be able to put enormous forces on the ground rapidly before we have a chance to block them. If that happened, the gulf would be lost."

Other members of the commission are W. Graham Claytor, Navy secretary and deputy defense secretary under President Jimmy Carter; retired Army general Andrew J. Goodpaster, former head of the U.S. Military Academy; retired admiral James L. Holloway, former chief of naval operations; political science Prof. Samuel P. Huntington of Harvard; Joshua Lederberg, president of Rockefeller University; retired general Bernard A. Schriever, former head of the Air Force Systems Command, and retired Army general John W. Vessey, former chairman of the Joint Chiefs of Staff.

The commission got off to a rocky start, according to informed sources. One participant said that at an early session, several civilians on the panel "wanted to do away with airplanes and ships and shoot the bad guys from Omaha {headquarters of the Strategic Air Command} with smart weapons. It never occurred to them that you might have to go after some guys in the Zagros Mountains {in Iran} and that we shouldn't throw away the good we have. Some of these guys have never been out there and seen what works and what doesn't."

Kissinger, sources said, refused to sign an early version of the report, complaining it belittled such Nixon administration accomplishments as the opening to China. The offending language was deleted or revised. Kissinger signed the final report, sources said.

Wohlstetter's firm, Pan Heuristics of Marina del Rey, Calif., did extensive work for the commission. Wohlstetter said he had nothing to do with Pentagon contracts awarded to Pan Heuristics or any other firm during the study and that he received no fee for his work. Col. Robert Rosenkranz, an aide to Pentagon aide Ikle, confirmed that Pan Heuristics material was used and that five of its employees served as consultants to the commission. He said, however, that Pan Heuristics' work came from existing contracts rather than ones let by the commission and that the firm's consultants were not paid.

Section 5 of the Federal Advisory Committee Act, which governs such advisory commissions, requires that "the membership be fairly balanced in terms of points of view represented." One commissioner said all the members are hawkish conservatives "who endorsed SDI under a different name" in the report. No strong opponent of SDI was on the panel.

"This is not a loaded document at all," Wohlstetter said, adding that the report's comments on antiballistic missile systems were constrained and not focused "on the president's program."

Officials said the GAO is also investigating complaints that the commission held no public hearings before issuing its public report, filed no descriptions in The Federal Register of what transpired in closed meetings and flew many commissioners and staff members from Washington to San Diego in August at great expense.

The Governmental Affairs subcommittee on oversight of government management, chaired by Sen. Carl Levin (D-Mich.), after studying the GAO report may recommend holding hearings on how the commission operated, congressional officials said.