Admitted spy John Anthony Walker Jr. told the FBI he forged a paper giving him his last Navy security clearance, according to papers ordered disclosed today to defense laywers for retired Navy communications specialist Jerry Alfred Whitworth.

U.S. District Judge John P. Vukasin Jr. ordered prosecutors to turn over that information to Whitworth's defense lawyers because it related to the reliability of Walker, the government's star witness in Whitworth's espionage trial.

Walker told the FBI about the forgery in an interview after his agreement in October to plead guilty to espionage and testify against Whitworth.

The record of the interview that Vukasin ordered be given to defense lawyers was not made public.

However, a source familiar with the case said Walker, fearful that he would not pass a polygraph examination, forged papers making it appear that his security clearance had been updated. The source said the forgery took place in 1971 or 1972.

The disclosure that Walker forged his security clearance recalled problems with military security procedures brought to light by the arrests in the Walker case last summer.

As a result of the arrests, the Defense Department instituted a number of measures to tighten control of classified information and keep better tabs on people authorized to see it.

Vukasin also told prosecutors to disclose parts of interviews in which Walker made statements that appeared to be inconsistent with his testimony on direct examination.

Walker testified Monday that, after his initial visit to the Soviet Embassy in Northwest Washington in 1968, his next contact with the Soviets was a meeting a month or two later at a Zayre department store in Northern Virginia.

Vukasin said in court today, however, that records of Walker's interviews with the FBI indicate another "event" took place between those two meetings. He did not specify what the event was.

Cross-examination of Walker started Thursday and is to resume Monday.

Whitworth, 46, the last of four Navy men arrested in the Walker spy ring to face trial, is charged with 13 counts of espionage and federal income tax violations. He allegedly received $332,000 from Walker for providing him with photographs of Navy codes and other classified information.