World Bank President A. W. Clausen has decided to reorganize the agency's influential economic research department with the aim of eliminating overlapping functions and bolstering the strength of operating divisions dealing with specific countries or regions.

Clausen revealed his plans over the weekend at a private session for World Bank vice presidents at the Wye Foundation on the Maryland Eastern Shore, the first head-to-head, relaxed discussion of bank affairs and policies by a World Bank president and his top staff.

Rumors of a shake-up of the research group, now directed by Vice President for Development Policy Hollis Chenery, have spread through the bank ever since Chenery indicated he would leave his job early next year to begin a lecture series at Harvard University.

Meanwhile, the bank is operating under a streamlined managing committee, designed to dramatically change the operation from the one-man control exercised by former President Robert S. McNamara to what Clausen describes as a "collegial decision-making process" in which subordinate officers are encouraged to use the authority delegated to them.

Clausen is expected to inform the staff today of the impending changes in the Chenery shop and to publicly announce the new managing committee later this week.

Chenery, who had been close to McNamara, heads a staff of 157 professionals providing basic macro-economic analysis and projections for the bank. But according to sources in the bank, there has been a growing feeling that the lending institution needs to concentrate more attention on micro, or sectoral problems affecting the development needs of Third World countries, and less on what some apparently consider theoretical economics.

"Clausen wants to get more of the pragmatic economists into the working sections of the bank," one official told The Washington Post.

The plan, therefore, is to take out of the Chenery shop some 30 to 35 economists or other professionals and transfer them to the projects staff under Vice President Warren Baum, to whom 397 professionals presently report. Some of the group to be moved, for example, will concentrate on African problems, a growing area of concern for the bank.

Also, Clausen intends to eliminate some functions that are duplicative in the industry and agriculture sections of both the Chenery and Baum operations.

Chenery, who will continue as an adviser to the bank through 1982, was reported to be upset by some of the planned changes, but officials said yesterday that the plans would not be completed until next March, and that he would continue to have a role in the final shape of the research unit organization. Speculation over Chenery's successor has focused on economist Robert Heller of Bank of America.

Clausen's general design for the revised Chenery and Baum operations was debated on Monday by the new managing committee of the bank, set up by Clausen within the first few weeks after he took over in midsummer in an effort to make the 5,500-member bureaucracy more efficient.

According to insiders, Clausen was stunned to find out that under the system he inherited from McNamara, the president was called on to make virtually all policy decisions in the bank. The 19 vice presidents of the bank were formed into a president's council, which was little more than a debating society.

Now, a regular Monday meeting of the managing committee, with Clausen as chairman, is responsible for all decisions.