The black leader described by the FBI as a cooperative contact in its undercover campaign to discredit the late Rev. Martin Luther King Jr. repudiated any such sympathies more than two years ago in an interview with Senate investigators.

The FBI's claims were publicized earlier this week as the result of a newly declassified Dec. 1, 1964, FBI memo that said an "ambitious" black leader, whose name was deleted, was apparently willing to work with the bureau "to remove King from the national picture."

In fact, according to informed sources, the memo actually referred to Roy Wilkings then NAACP executive secretary, who had met several days earlier, on Nov. 27, 1964, with FBI assistant director Cartha DeLoach about the bureau's attitude toward Dr. King.

In a memo written that same day, Nov. 27, DeLoach pictured Wilkins as apprehensive and said the meeting ended with Wilkins promising to "tell King that he can't win in a battle with the FBI and that the best thing for him to do is to retire from public life."

Wilkins, however, told the staff of the Senate Intelligence Committee in the fall of 1975 that DeLoach's account was "self-serving and full of inaccuracies." The NAACP official, now retired, denounced the remarks attributed to him as "pure invention" and indicated he had done little more than express his concern "that accusations about Dr. King would cripple the civil rights movement."

The Dec. 1, 1964, followup memo, written by FBI official J. A. Sizoo to suggest further action Dr. King, picked up some of DeLoach's heretofore unpublicized remarks about Wilkins, senate investigators had been privy to the remarks but never made them public. The Sizoo memo, with Wilkins' name deleted, was finally obtained from the FBI under the Freedom of Information Act by the nonprofit Center for National Security Studies.

Its release this week left the impression that the momentarily anonymous black leader mentioned in the Sizoo memo might be the same person as the new - and much younger - "national Negro leader" that the FBI had once secretly nominated to take over the civil rights movement after King had been "completely discredited." Informed sources, however, said yesterday man. His name has never been made public, ostensibly because he was never told of the FBI's plans for him.