A ''big ten'' power structure in the Reagan administration is now emerging.
These influential members of the adminstration include White House staffers and Cabinet members. What they have in common is access to the President. But the degree of access shifts almost constantly, according to key political observers, depending on what staff or Cabinet member Mr. Reagan is turning to at the moment.
The triumvirate that first gained prominence in the White House was the so-called ''big three'': James A. Baker III, chief of staff; Michael K. Deaver, his deputy; and Edwin Meese III, counselor to the president.
Then the group became a ''big four,'' with the inclusion of William P. Clark, assistant to the president for national security affairs. But some analysts say the circle of close Reagan advisors is even larger. As the administration reaches its 16th month, political observers here conclude that the cabinet members frequently in the power center are:
Secretary of State Alexander M. Haig Jr., Secretary of Treasury Donald T. Regan, Vice-President George Bush, Secretary of Defense Caspar W. Weinberger, Attorney General William French Smith, and CIA Director William J. Casey.
Who are tops among these 10? The President would give that rating to his Cabinet members, calling his staff people functionaries, not vital movers and shakers.
Yet, as viewed from both outside and inside the administration, the key staff people who spend hour after hour with the President and thus constantly reflect his influence -- Mssrs. Meese, Clark, Baker, and Deaver -- are seen to have the most clout.
''They even send out vibes of fear to Cabinet members,'' one official told the Monitor. ''That's because even when they speak quietly and politely -- as the Reagan people usually do -- they are very visibly speaking for the President.''
Within the White House, Chief of Staff Baker is usually said to carry the biggest stick -- although he, like Clark, Deaver, and Meese, is low-keyed and friendly in manner.
''It (influence) really changes from day to day,'' one administration aide says, ''depending on who is seeing the President the most that day. Sometimes it's Meese, sometimes Clark, sometimes Baker, sometimes Deaver.''
One White House aide who watches the dancing around the President has a different view: ''In terms of influence, I happen to think that Deaver has the most confidence of the President. He is so very comfortable with the President.''
There are those, even within the administration, who raise questions about the power positions attained by the ''big four.'' Said one person high up in the administration:
''They were never elected to anything or confirmed by the Senate. But they have assumed immense influence because of their proximity to the President and their important staff functions. We've seen this happen in previous administrations -- sometimes working out well, sometimes not.''
There is an often-heard view among president watchers that influential staff people often shield a president from information he should know -- that they sometimes isolate him from the real world. This charge is not being made of Reagan's ''big Four.''
In fact, the opinion of these watchers is that Reagan has a particularly able group of assistants at his elbow. Further, it appears that the top staff men get along well with the Cabinet and Congress, and that the White House as a whole operates in a relatively harmonious way.
The six Cabinet members now accounted to be the most powerful also deal frequently with the President.
The presence of Secretary Haig in this group would be expected, considering the importance of his assignment and the necessity for him to confer often with the President. Secretary Weinberger is in the inner circle for the same reason. But Weinberger is also there because of his long personal and political ties with Mr. Reagan.
Mr. Regan has earned his way onto the Reagan first team. Reagan respects Regan and his opinions, say White House insiders and Washington observers.
The vice-president, too, has won the President's respect. Mr. Bush sees Reagan almost every day. He counsels him on both domestic matters and foreign affairs. ''Sometimes,'' one White House aide says, ''Bush might be No. 6 as far as influence is concerned. But on some days he is No. 1.''
There has been some speculation in Washington of late that Attorney General Smith might have lost some of his standing with the President. Mr. Smith has been under criticism because of tax deductions for a type of investment shelter frequently disallowed by the Internal Revenue Service.
But it is clear Reagan is holding firm behind his attorney general and, hence , Smith remains highly influential.
Are there others who might be a part of Reagan's inner circle? David Stockman , director of the Office of Management and Budget, was there. Then, after an article in The Atlantic magazine, he plummeted from the position.
Some say Stockman may be back in favor once again. Others argue that once the budget is done, the President will encourage Stockman to take another government position.