Tired of keeping your Christmas card list up to date? Of addressing all those envelopes by hand?

Not to worry. Big Brother . . . er, Uncle Sam wants to do it for you. And that's got some people concerned about the privacy of you and your friends.The U.S. Postal Service is proposing to keep computer files of individual and business holiday card address lists to help it handle the enormous volume of handwritten envelopes during the holiday season.

A test of the plan starts this Christmas in Akron, Ohio. If it succeeds, it will be expanded nationwide.

Here's how the "Customer Holiday Address List" program is supposed to work: If you give the post office your address list, it will send you a set of mailing labels that you can stick on your envelopes. The labels will carry pre-printed bar codes that automatic mail sorting machines can "read."

The Postal Service will also keep your list on file so next year you can scratch out Cousin Alice, who didn't send you a card last year, and add your new boss and his wife.

This sounds great, but some people are worried that people's privacy may be threatened. The FBI, Internal Revenue Service and other law enforcement agencies can get access to the lists, and might be interested in seeing who is on, say, Charles Keating's list. Keating is the savings and loan executive whose contributions to five U.S. senators have caused a national scandal.

"The permanent maintenance of a customer mailing list is a dangerous invasion of privacy," said Rep. Robert Wise, D-W.Va., chairman of the House Subcommittee on Information.

"It is a threat both to those who send mail using this program, and to those who receive it," Wise said in a letter to Postmaster General Anthony Frank.

"Imagine the surprise of an individual who was visited by the FBI because he sent a Christmas card to or received a Christmas card from . . . a target of a criminal investigation," he wrote.

Wise also noted that many doctors, charities and political advocacy groups send holiday greeting cards to their patients or supporters. Disclosure of their names could be embarrassing or lead to political and legal problems.

"Would either a doctor or patient be secure knowing that the doctor's customer list resided permanently in the Postal Service computers?" Wise asked.

The Postal Service defended its plan. "Use of this system should have no effect on individual privacy rights," said Stanley Mires, assistant general counsel. "The original mailing list is returned to the customer. Only a copy of the list in pre-barcoded format will be kept strictly for purposes of customer reordering."

Betty Sheriff, a privacy official in the Postal Service, acknowledged, however, that the address lists could be made available to law enforcement authorities.

She said the holiday address list would "absolutely not" be provided to commercial customers, such as credit bureaus, private investigators or mail order houses.

However, private organizations now can purchase the Postal Service's computerized "national change of address" files, which list the names and addresses of anybody who moves. It is only a matter of Postal Service policy - not law - which keeps the holiday address list out of commercial hands.