University of the District of Columbia Trustee Donald A. Brown said yesterday that UDC President Robert L. Green should be placed on administrative leave until the board of trustees "can sort out allegations" that Green misspent thousands of dollars of university funds.

Brown, the third of 15 trustees to call publicly for Green to step aside, said Green "has made sufficient errors of judgment to make him at the present time a liability to the school."

The FBI last week began investigating allegations of financial improprieties by Green and other officials at the publicly financed university. D.C. Auditor Otis H. Troupe, in a report released last week, said Green owed the university $13,000 in funds that Troupe said Green misspent.

Gilbert Maddox, a spokesman for Green, said yesterday that the "president has indicated categorically that he has no intention of taking administrative leave. He sees no reason for it."

Trustees F.D.R. Fox and Joseph Webb have said that Green should step aside or resign. Two other trustees, who have declined to speak out publicly, have indicated privately that they want Green step down. Brown, a Washington developer who has served on the board for nearly two years, said his decision was "particularly painful" because he thinks Green cares for and has worked hard for UDC and has not acted illegally or dishonestly.

"As an educator I have enormous respect for him . . . ," Brown said during an interview. "My conclusion is that because of the damage being done to the university . . . it is appropriate that he be put on leave until the board of trustees can sort out all the allegations of misconduct and come to a judicious determination of what best ought to happen to protect UDC."

Brown said allegations that Green had traveled and entertained excessively since taking office in September 1983 "don't impress me at all . . . But I have come to the conclusion that Green has not been a victim of any malicious vendetta by the press, and I am totally convinced he is not a victim of racism," said Brown, who is white.

Brown said he was particularly bothered by "the number and extent and use of consultants" who did not appear to be sufficiently qualified