Many federal workers are concerned by government plans to crack down on telephone abuse by using computer lists to track nonbusiness calls dialed from the office. The government says the system isn't intended to stop employes from calling home to check on children or to talk briefly with spouses or friends. The primary purpose, the government says, is to stop nonbusiness long-distance calls.

Government employe unions, civil liberties groups and others have complained that the system -- in which supervisors will get regular computer printouts of all telephone numbers dialed from their offices -- could be used to intimidate workers. Many private firms already use similar systems to see if employes are misusing long-distance telephone lines.

While most readers have expressed concern about the "Big Brother" potential of the system, some employes say there is another side to it:

* "Much has been said about the dangerous potential of the system, but there is another side to it. I am a government worker and have for years observed coworkers misusing telephone long-distance lines to chat for hours with friends, to dial weather in other cities or to keep in touch with relatives.

"Cleanup crews in the evening are frequent abusers of the telephones and some workers who get brownie points for coming in on weekends to 'work' are actually in the office so they can use the telephone. Obviously there is a 'Big Brother' potential to the computer monitoring, although monitoring all calls would be a big job. But there is one easy way to avoid getting in trouble. Just use the telephone for business." B.C., Arlington.

* "The telephone monitoring plan can't come soon enough to suit me. The office idiot spends one-third of his day calling dial-a-joke numbers in New York City and other places and then relaying the jokes to us, his 'captive audience.' Some of the jokes are filthy, most are not very funny. I'm a taxpayer too, but when we complain to the boss, he says it is 'no big deal,' and the jokes keep coming." Signed: Not Laughing!

Other letters this week look back on the issues of smoking, whether federal workers are overpaid and religious services:

* "Here is how we took care of the smoking problem a few years ago. We simply don't allow smoking, except in authorized areas. Every new employe is advised of the no-smoking rule and, although I'm sure some longtime employes who are smokers have had difficulty . . . abstaining -- you know what? The rule works." Esther P. Gelman, a member of the Montgomery County Council.

* "In a letter in your column, a National Institutes of Health employe complained, 'I can't sign my name because our agency director smokes a pipe.' The employe is misinformed. NIH Director Dr. James B. Wyngaarden is not, and never has been, a smoker." Storm Whaley, associate director for communications.

* "The letter from the Silver Spring man advised us 'overpaid' federal workers to quit if we don't like it. He sounds like a very frustrated person who was never a success and, from his attitude, never will be.

"Let me make a couple of things clear: I am not overpaid. I come to work early, leave late and work weekends. Why? Because my office is understaffed. Why not quit? I have too much invested in the government and my career. As a matter of fact, if we government employes are so overpaid, why doesn't the man from Silver Spring apply for a government job?" O.P.S., Springfield.