The flap over whether or not the federal government should use lie detectors to check up on its employes is spreading into the private sector. Hearings on the issue are scheduled this week before the Senate Labor Committee, and Congress is likely this session to impose some curbs on corporate use of the devices.

"I don't think there is any question but that polygraphs are intimidating and humiliating," Rep. James M. Jeffords (R-Vt.) said last month. "And if they do not actually violate an individual's rights to speech, privacy and freedom from self-incrimination, they sure come close."

Jeffords was leading the fight in the House for a bill -- quite similar to the one at the center of the Senate hearings this week -- that would ban use of the polygraphs by any company affecting interstate commerce. The House carved some exceptions into that ban, but turned down bids to let banks and casinos continue to use the devices. It passed the basic prohibition by a vote of 236 to 173.

The Senate bill stands a good chance of passage, too: it is jointly sponsored by the senior Republican and Democrat on the committee, Orrin Hatch (R-Utah) and Edward M. Kennedy (D-Mass.), who usually find themselves at opposite poles politically.

And the measures will require a real change on the part of American business; employers, not law-enforcement agencies, gave some 98 percent of the estimated 2 million polygraph exams administered last year. Some of the industry probes are an attempt to find culprits in particular thefts, but the vast majority are a routine part of the hiring process. And the practice is on the increase: a decade ago, fewer than 700,000 polygraph examinations were administered annually.

Business says it needs the additional screening provided by a lie detector to combat losses from employe theft and fraud -- losses that may come to as much as $50 billion a year, according to Rep. George W. Darden (D-Ga.), an opponent of a federal ban on private-workplace testing.

Advocates insist that the device is as much a tool to protect the innocent as it is a way of catching the guilty. "In my own business, I have repeatedly used the polygraph to protect individuals in situations where they are suspect," said Rep. Patrick L. Swindall (R-Ga.), a furniture-store owner. "I, for one, have on numbers of occasions hired former felons, and one of their protections is, when an individual accuses them wrongly, they can go to a polygraph examination and vindicate themselves."

Increasing exposure to liability suits is yet another reason the companies argue that lie detector exams make good sense. With plaintiffs charging that companies negligently hired inappropriate persons for jobs ranging from hospital orderlies to store guards, the company wants to build as persuasive a record of care-taking as possible.

Those arguments are countered by the twin complaints that polygraphs are intrusive and ineffective. Organized labor has made the ban a top legislative priority, arguing that the device can be used by management to intimidate workers. "We very much wanted this bill," AFL-CIO spokesman Murray Seegar said after the victory on the House.

The lawmakers who supported the bill are suggesting that given the ways corporations govern our lives, they should have to live with some of the same prohibitions that the Bill of Rights imposes on true governments. Rep. Matthew Martinez (D-Calif.), chairman of the subcommittee that originally handled the House bill, said polygraph tests violate such standards as the presumption of innocence and the right to due process.

But the practical arguments about the reliability of the technique are closely tied to the theoretical constitutional arguments. Actions curbing liberties are all the more unacceptable if they are unreasonable, and it is unreasonable almost by definition to use a screening device that does not screen accurately. Three years ago, the Office of Technology Assessment looked into the record of polygraph predictions and unearthed studies finding the results wrong anywhere from twice in a hundred examinations to as much as 36 times in a hundred. Some villains seem able to lie with no emotional trauma, while some honest persons are so nervous that they trigger a polygraph warning with nothing more than memories of some schoolyard naughtiness decades ago. But even if the most optimistic estimate about the usefulness of the technique is right, turning down two job applicants out of a hundred for unfair reasons is too many, the supporters of the ban insist.

But although a majority seems to believe that polygraph tests are dangerously unreliable, the lawmakers continue to allow governments -- and contractors for such agencies as the Central Intelligence Agency and the National Security Agency -- to use the technique.

They also wrote into the measure permission for drug companies, hire-a-guard outfits, public utilities and day care centers to continue to use polygraphs. The reason: They have special problems with security. That may not show entirely logical reasoning, but political victories are won not with logic but with compromises that, like the nonaerodynamic bumblebee, manage to defy logic and fly.