A New York federal judge will hear arguments today on whether a suit against George Mair, former publisher of The Alexandria Gazette, violates his First Amendment rights and whether public relations firms can legally insist that former employes maintain the confidentiality of relationships with clients.

Public relations firm Carl Byoir & Associates sued in October to stop publication of Mair's book, "Inside Home Box Office: The Cash Cow That Almost Ate Hollywood." A month before, Mair had left his part-time consultant position with Byoir, where he had worked for almost a year on a Home Box Office account.

Since then, Mair, 56, who lives in Alexandria, has written his book, to be published by Dodd, Mead and Co. early next year. HBO, the country's largest pay-television network and a centerpiece of the book, is owned by Time Inc.

Mair has characterized the suit as an indirect move by Time Inc. to "suppress" the book's publication.

Michael Luftman, a spokesman for Time Inc., said "this is totally out-and-out false. Time Inc. has never attempted to stop publication of any book."

Said Harold Suckenik, attorney for Byoir: "We are claiming he violates the well-known code among public relations executives not to disclose confidential information. It doesn't have to be in writing, it rises out of the employer-employe relations."

Byoir wants to stop publication of the book and to read the manuscript to determine whether confidential material about HBO was used. Byoir also seeks money for damages.

James Hamilton, an attorney for Mair, said the suit "was seeking a prior restraint. That isn't cricket unless you have some extraordinary national security issues. And they are claiming damages. We are saying they don't have any injury because the book hasn't been published."

Mair said HBO is highlighted in "33 to 40 percent" of the book as an example of the growth of the industry. "It is the most dramatic business success story of the last decade . . . I think it is a reasonably balanced treatment."

Suckenik said that "it seems to be a valid assumption that somewhere during the year of employment, he learned a lot about HBO. Look at the fortuitous circumstances, that he took the job, and that a month after he left, he announced he was writing the book."

Suckenik also argued that "we are not the government so the First Amendment does not apply."