President Neil L. Rudenstine has been a busy man since he took office July 1. He has had people to meet, speeches to make and letters to write.

But one of his most time-consuming tasks so far, according to his co-workers in Massachusetts Hall, has been that of finding the right people to fill at least six major vacant or soon-to-be-vacant administrative positions.

The choice of Jeremy R. Knowles as dean of the Faculty of Arts and Sciences (FAS) last June completed Rudenstine's first major search and selection process. But he and the advisory committees he has created still have several slots to fill, including three new graduate school deans and a new vice president and general counsel, among others.

Despite Rudenstine's burdensome workload ahead, University officials say that it is by no means unusual for a new president to be faced with such a large number of positions to fill at the beginning of his term, especially since some of the outgoing administrators are people who came into office at around the same time as former President Derek C. Bok and are just ready to retire.

By this time next year there will be hardly a branch of the University administration that has not had at least one major appointment by Rudenstine. From FAS to the Office for Affirmative, Action, this is Rudenstine's prime opportunity to determine the makeup of the administration that will bear his name.

Besides choosing individuals to fill existing slots, Rudenstine may choose to create new ones entirely. When Bok took office in 1971, he created three new vice-presidencies and expanded the rest of the president's administrative staff significantly.

Many expect Rudenstine to revive the position of provost, which last existed at Harvard in the 1940s. Rudenstine has said he believes that a provost, who would have a University-wide perspective similar to the president's, would help him achieve his goal of bringing the disparate parts of the University closer together. Rudenstine himself spent more than a decade as provost of Princeton University before stepping down in 1987.

Rudenstine's colleagues say that he is close to making a final decision as to whether or not he will appoint a provost. For now, they say, he is continuing to gather reactions to the idea from members of the University community.

In the meantime, he is busy trying to fill another highly influential position, the Corporation seat left empty by the death of Colman M. Mockler, Jr. '52 during the presidential search. The seven-member Corporation, Harvard's primary governing body, meets twice a month to determine University policies and investments.

University officials say that the process of discussing and choosing a replacement for Mockler is now underway. A five-member search committee has been established, consisting of Rudenstine, University Treasurer D. Ronald Daniel, Overseers President Franklin D. Raines '71, Overseer Peter L. Malkin '55, and senior Corporation member Charles P. Slichter '45. The committee has met once so far.

University observers say that the committee members are likely to look for someone with business and financial expertise comparable to that of Mockler, who was chief executive officer of Gillette Co.

The searches for replacements for the three graduate school deans, which are presumably also high on Rudenstine's list of hiring priorities, are in varying stages of completion.

The selection of a successor for Graduate School of Education Dean Patricia A. Graham is apparently nearing its final stages. Linda Darling-Hammond, a professor at Columbia Teacher's College in New York, is said to be one of the top candidates for the post.

The unexpected resignation of Kennedy School of Government Dean Robert D. Putnam last June left Rudenstine with yet one more vacant post. Putnam, who said he wanted to return to scholarship and teaching, had been dean for the relatively brief period of two years.

Over the summer, Rudenstine named a Kennedy School advisory committee, which has begun looking for a replacement for Putnam. The school's acting dean, Albert Carnesale, is said to be a contender. A decision is likely to be made before the spring semester.

The final deanship appointment Rudenstine must make is at the Graduate School of Design. Gerald M. McCue, the school's dean, announced in June that he would be stepping down at the end of this year after 12 years at his post.

McCue said last week that the task of finding his successor is still in its earliest stages, explaining that Rudenstine has only recently named an advisory committee.