Even as the Reagan administration appears to be backing down on its controversial plan to use lie detectors to ferret out news leaks, the Defense Department is trying to increase the use of polygraph exams.
The White House also has temporarily shelved a proposal to prevent former government officials from publishing works containing sensitive information.
In a recent letter to Rep. Patricia Schroeder (D) of Colorado, national security adviser Robert C. McFarlane said that in the face of congressional opposition, President Reagan has decided not to proceed with these two issues ''for the duration of this session of Congress.''
Lawmakers last year barred the administration from implementing the two plans before April 15 of this year, and congressional hearings on the subject are continuing.
The Pentagon, meanwhile, is pressing its case for greater use of polygraphs for counterintelligence purposes. Faced with a recent spate of espionage cases, defense officials want to conduct more of the controversial exams on persons applying for sensitive jobs. This would include federal employees (especially intelligence personnel) already working for the government and seeking promotions or transfer.
Those who refuse to take such tests would automatically be barred from such jobs, a fact civil libertarians and other critics say could harm careers. Officials also want to be able to conduct lie detector tests at random among tens of thousands of employees working in defense intelligence agencies.
Some studies show that polygraphs can help weed out potential security risks. There have been recent cases of this happening. One applicant for employment with the National Security Agency (a retired military person) admitted under polygraph examination that he had recently visited the Soviet Embassy to talk about defecting. Officials also say that lie detectors can be a strong deterrent , regardless of their accuracy.
''We are convinced the polygraph process works,'' Defense Undersecretary Richard G. Stilwell told a recent congressional panel. Mr. Stilwell, a retired Army general, detailed the various safeguards the Pentagon plans to employ, and stressed that ''the polygraph is to be used only as an aid in support of other investigative techniques.''
Yet many experts warn that recent developments make it possible for spies to be trained to spoof the machine using drugs, hypnosis, biofeedback, or even something as simple as biting one's tongue.
''My professional conclusion is that employment of so-called lie detector tests is likely to lead to a detriment in security of classified information rather than enhanced security,'' says Dr. Leonard Saxe of Boston University, principal author of a recent study on polygraph testing by the US Office of Technology Assessment.
Over the past decade, the use of lie detector tests by federal agencies has more than tripled. The Defense Department two years ago stepped up its use of polygraph tests. Officials said this was needed to counter growing espionage, especially the transfer of advanced US technology to the Soviet Union. Increases in privacy protection had inhibited traditional background investigations, officials complained. At the same time, even proponents of polygraph testing to screen prospective employees in sensitive areas admit that practice has outpaced research in using lie detectors for such purposes.
David C. Raskin, a University of Utah psychologist who trains and evaluates polygraph examiners, says, ''A carefully managed and restricted application of polygraph examinations seems reasonable as long as adequate safeguards are provided.''
But in recent Senate testimony, Dr. Raskin also noted a ''lack of oversight procedures,'' and said, ''The personnel who train federal polygraph examiners are grossly deficient in the psychological, physiological, and scientific knowledge which is required to conduct an adequate and effective training program.''
In his letter to Representative Schroeder, who heads the House subcommittee on civil service, Mr. McFarlane said: ''Rather than resume the legislative debate . . . we would prefer to work cooperatively with Congress to develop a mutually acceptable solution to this problem.''
But administration officials emphasize that they want to step up the use of lie detectors in any case (as General Stilwell says) to ensure ''that our most sensitive programs are not penetrated by hostile intelligence agents.''