It Zbigniew Brzezinski is ever transformed into an all-powerful replica of Henry A. Kissinger in the Carter White House, it will not be for any lack of assurances that it will not happen.

No other office in the Carter administration is being established with comparable declarations about what it will not do.

Foremost among the assurers is Brzezinski, who has his National Security Council staff nearly three-fourths completed. Figuratively hanging over Brzezinski's operation is an array of warnings by President Carter and Brzezinski of the dangers that reside in the aggrandizement of power and "Lone Ranger" diplomacy.

Looking on, not dispassionately, are veterans and newcomers at State, Treasury and other departments. They learned from the Kissinger era that ambition, plus proximity to the President, can outweigh any diffusion of power that is proclaimed or inscribed on organizational charts. Only experience will dispel, or confirm, suspicions that Brezezinski might duplicate Kissinger in converting the post of presidential national security affairs adviser into a launching pad for preemininence in the government.

There are fundamental differences, however, at the outset. Not least of them is the attitude of the No. 1 man in the White House.

President Nixon wanted foreign policy to be run out of the White House with utmost secrecy; he and Kissinger shared disdain or distrust of the bureaucracy. President Carter and Brzezinski have proclaimed the opposite approach.Carter, in addition, has been insistent that he alone will control the formulation of policy.

Kissinger, before coming to office, said, "It is dangerous to separate (policy) planning from the responsibility for execution." But he embraced that danger, nevertheless, on grounds that "only way secrecy can be kept is to exclude from the making of the decision all those who are theoretically charged with carrying it out."

Brzezinski, though no less eager than Kissinger to display dynamic capacities, last week took the opposite tack:

"I conceive my challenge to be to prove that in a highly complex world of political, economic and security challenges, a team effort can work. Anything less than a team effort would not give us the kind of comprehensive policy that we need," he said.

Brzezinski recognizes that critics are bound to scoff. But the 48-year-old former Columbia University professor maintains that not only does he mean it, but that Carter, who called himself Brzezinski's "eager student" in world affairs, means it most of all.

The President took a direct hand in designing the new NSC staff system, another source said, and "threw out" the original structure submitted to him on grounds that it was too complex and inflexible.

What the new NSC operation intends, it is said, is "to put more authority back into the departments," to fix responsibility for an issue in a single department to the maximum extent possible and to give the president opportunity to participate in the system when he desires.

Brzezinski's NSC deputy is David L. Aaron, 38, a former Kissinger NSC staff member and later foreign policy adviser to Walter F. Mondale, who directed the NSC transition staff.

The new NSC staff accents youth, imaginativeness, doctoral degrees and a more liberal political orientation than the staffs that more recently worked for Kissinger or his successor, Brent Scowcroft.

A leaner, "more collegial" system is planned with a cut from about 50 staff members at the Kissinger peak to about 30 for Brzezinski.

Instead of seven interdepartmental committees chaired or dominated by Kissinger, there will be two. One is the Policy Review Committee, to include formal NSC members (the secretaries of State, Defense and Treasury, director of Central Intelligence, chairman of the Joint Chiefs of Staff is to coordinate policy and to serve as a "think tanent) plus other agencies as required. Chairmanship will depend on the subject; Carter may join in. The other is the Special Coordinating Committee, chaired by Brzezinski, on crises, covert intelligence operations and what are labeled "cross-cutting issues," such as arms control policy.

(Brzezski also is a member of the administration's Economic Policy Group).

The declared purpose of the NSC staff is to coordinate policy and to serve as a "think tank" rather than to make policy. That distinction disappeared in the Kissinger years - and may again.

Brzezinski has looked for staffers described as "sensitive to the global challenge." He has created a Global Issues Office to cover a range of subjects from U.N. affairs to arms sales, nuclear weapons proliferation and human rights.

Heading this office will be Jessica Tuchman, 30, daughter of historian Barbara Tuckman. Jessica Tuchman received a Ph.D. in nuclear biophysics and biochemistry after studying three years at California institute of Technology and two years at Massachusetts Institute of Technology.

A North-South office will encompass Latin American, African and Asian issues. It still lacks a chief; Robert O. Pastor, 29, of Harvard has been named for Latin American affairs.

Other offices and staffers are:

European affairs - William G. Hyland, former Central Intelligence Agency official, senior adviser to Kissinger on Soviet affairs, State Department intelligence director and, most recently, NSC deputy to Scowcroft. Also, Robert P. Hunter, foreign affairs adviser to Sen. Edward M. Kennedy (D. Mass.).

Middle East affairs - William Quant former NSC staffer under Kissinger, later on the faculty of the University of Pennsylvania.

Far Eastern affairs - for China, Michael Oxenberg, professor at the University of Michigan; for Japan, Michapel H. Armacost, Foreign Service officer.

Policy Analysis Office - headed by Victor A. Utgoff, from the Center for Naval Analysis, a Ph.D. in electrical engineering from Purdue, specialist on weapons and strategy; also NSC holdover Roger Molander, specialist on nuclear strategic arms.

Economics - chief still unnamed; to include holdover Robert D. Hormats.

Intelligence - Includes holdovers Samuel Hoskinson, former CIA national intelligence officer, and Air Force Co. Robert Rosenberg.

Other NSC staff members include special assistant Karl F. (Rick) Inderfurth. 30, former legislative assistant to Sen. Gary W. Hart (D-Colo.) who worked on the special and current Senate intelligence committees; also Col. William Odum of West Point.

Among Washington power-watchers, interest was piqued last week when Brzezinski added as a staff member a veteran journalist, Jerrold L. Schecter, 44, diplomatic editor of Time magazine, with the title of "associate press secretary congressional liaison, National Security Council." In the past, NSC press liaison has been a routine function.

Brezinski disclaims any aggrandizing intentions. He also maintains that the rivalry that developed between Kissinger and other Cabinet members is doubly unlikely in his case because of the shift in the NSC pattern, and especially because of his prior close friendship with current Cabinet members.

He was associated with Secretary of State Cyrus R. Vance, Defense Secretary Harold Brown and Treasury Secretary W. Michael Blumenthal on the Brzezinski-initiated Trilateral Commission, and also worked closely with Vance on other projects.

Vance, in any event, is moving out to establish primacy as Carter's global envoy. He already has scheduled a February trip to the Middle East, and a March trip by Vance to the Soviet Union is projected.