FBI Director Louis J. Freeh is cutting the ranks of supervisors and administrators so he can move 600 of the bureau's 10,078 agents from desk work to street investigations.

"For too many years, FBI headquarters in Washington has been top-heavy with supervisors and unnecessary levels of review and decisionmaking," he told a news conference Thursday."With crime so grave . . . we need fewer agents behind desks and more on the streets investigating and arresting criminals, corrupt public officials, spies, drug dealers, mobsters, gang members and terrorists."

Within 60 days, 150 supervisors from headquarters will be transferred temporarily to investigations around the nation's capital.

By year's end, if the White House budget office and congressional committees agree, 300 supervisors will be transferred permanently to investigative work in the 56 FBI field offices around the nation. Relocating 300, or 37 percent, of the headquarters agents would cost $24 million, to be raised by cuts elsewhere in the Justice Department, Freeh said.

Subsequently, the field offices will move 300 other agents permanently from administrative duties to street investigations. The offices have not been selected yet.

The FBI has not had money to hire new agents since 1992 and does not expect to get any until 1996, Freeh said.

Freeh acted first in the Washington metropolitan area because of budget limitations, he said. He can move 150 agents temporarily to offices in Washington, Virginia and Maryland without transfer costs.