IF YOU CALLED Internal Revenue for advice during the tax season, you might have been talking to one more bureaucrat than you counted on - somebody who was eavesdropping. It's done supposedly to check on the accuracy and politness of the tax assistors, and you needn't give your name. But you might feel uneasy anyway. After all, there's only one IRS, and you can't avoid dealing with it.

Yet IRS is hardly alone in its desire to snoop.

"Random, bureaucreatic voyeurism appeals to many federal agencies," warns Sen. Max Baucus, chairman of a Judiciary subcommittee investigating electronic snooping in government. "They enjoy listening in on the public without the public's knowledge or permission."

"If we allow this to go unchallenged, it will grow to become an accepted fact of American life," says Baucus, who has demanded strong new regulations to reduce federal snooping. "There will be no limits to such bureaucratic meddling, all in the name of 'helping' us."

Such "help" sometimes comes from the Office of Personnel Management. If you call the office's Federal Job Information Centers, you may be monitored. The giant Social Security Administration no longer monitors, but wishes to resume. And the General Services Administration's Federal Information Centers, which steer citizens to the right agencies for help or facts, stopped the monitoring only when congressmen objected. "Consensual monitoring"

At least ordinary Americans aren't as likely to be secretly monitored or taped as federal workers are at GSA and elsewhere. GSA investigators have used such tactics during the agency's recent scandal-hunting. They can snoop away, without court orders, simply by assuring that one of the monitored persons consents. That's hardly a feat, since a GSA agent or informer can be the one agreeing to "consensual monitoring."

"For one party to determine that the other party's privacy is or is not being invaded makes no sense," protests John Shattuck, director of the Washington office of the American Civil Liberties Union. "When you're talking to someone, it's assumed you're only talking to that person and you're not talking for the record and your conversation isn't being permanently taken down so others can get access to it. It may be that the conversation will be repeated by the other person, but that will be his recollection, not a definite record." So Shattuck sees such situations as "really no different from a wiretap where neither party consents."

"Consensual monitoring" isn't an abstract issue for an IRS man named Joseph Mackin. In late 1977 he thought he was just chatting casually over coffee in a cafeteria in Philadelphia. He did not know that his friend, acting under the direction of the IRS Internal Security Division, was in effect taping a possible confession from him.

Indignant, the National Treasury Employees Union has filed a lawsuit challenging the taping and the written reprimand that ensued against Mackin.

"People were afraid to talk to their friends at work, because they were scared they might be on tape," says a union spokesman. "The incident's had a devastating effect on morale." Regulation delayed

Last year, worried by snooping at IRS and elsewhere, Rep. Dale Kildee and then-Rep. John Moss talked the Carter administration into proposing a regulation sharply reducing federal listen-in equipment. But the regualtion still isn't out. The GSA now promises it by the end of June. GSA has backed off from the original proposal it published in the Federal Register last June 27, which would have limited snooper gear to gadgetry needed for "public safety."

As recently as December 1978, GSA let IRS install equipment that the proposal would ban. Nor has GSA ruled out the possibility of a final version of the proposal that would allow such practises to continue.

Frank Carr, commissioner of GSA's Automated Data and Telecommunications Service, under whose guidance the regulation is being softened, says that even last year's version wouldn't have covered snooping not involving the federal phone system.

So, in person, snoops could still indulge in "consensual monitoring" against the likes of Joseph Mackin.

If last June's proposal somehow became a regulation without being watered down, however, there at least would be a wholesale reduction in "push-to-talk or push-to listen features on handsets and monitoring equipment for service training." IRS would have to yank out, or modify, the call distributors it installed recently in taxpayer assistance offices in Oakland, Louisville, Lexington and Boston. The distributors, besides helping IRS electronically cope with large numbers of people calling at once, have listen-in features.

Not surprisingly, IRS has bitterly fought last year's proposal. So has Labor, which wonders how it can get its new Inspector General's Office off the ground without enough freedom to snoop.

Housing and Urban Development says last year's proposal apparently could ban automatic answering services. Interior worries that the changes could, among other things, doom conference phone calls. HUD and Interior have geniune feelings for the gut issues of bureaucracy.

At least a dozen agencies have objected to the 1978 proposal because of its effects on service monitoring and "consensual monitoring" in investigation. Upheld by courts

And it must be conceded that the courts wave upheld both practices. Moreover, the government is far from being the sole perpetrator of service monitoring. Airlines and insurance companies do it, too, writes lawyer and privacy advocate Robert Ellis Smith in his recent book "Privacy: How to Protect What's Left of It." So do department stores.

But why can't federal agencies set examples for business and improve training programs so citizens can enjoy good, courteous service without snooping? Why can't bureaucracies insist on their workers identifying themselves by name on the phones so the public can report troublesome employes? Why can't inspectors make test calls posing as private citizens - a questionable practice, but better than eavesdropping on the public at large?

Most important of all, GSA should encourage alternatives by taking its anti-snooping role more seriously. It is, after all, the federal procurement agency, with vast powers over who uses what equipment. GSA even has a regulation saying agencies must tell it about applications of snooping gear. Yet over a period of several days, no one at GSA could give me even a good guess about the number of listen-in devices in government now.

If GSA is so sloppy in enforcing its regulations why not make them as strict as possible? Cumbersome regualtions against snooping can be changed. Gross violations of civil liberties & aren't always as correctable.