The National Book Awards, for 30 years among the most prestigious of literary honors, have been replaced by the new and more diverse American Book Awards.

In place of the panel of authors and critics who annually conferred the NBA on six or seven volumes fo fiction, belle lettres, poetry and biography, 2,000 members from the Association of American Publishers will choose the "best" works in 20 categories ranging farther into "popular" literature.

The new categories of first novel, western novel, science fiction, mystery, religion and inspiration, current interest (self-improvement, hobbies, life style, etc.) and reference books reflects the industry's longtime complaints that the National Book Awards were elitist and ignored the increasing sales of popular books.

In 13 of the new categories, there will be awards for both hardback and paperback books; books which do not win the first year will be eligible again as paperbacks another year.

There also will be awards for the best in book design and best jacket.

The Association of American Publishers has even hinted that it may commission a "major American artist" to create an Oscar-style statuette or plaque to be presented to the winners. The National Book Awards previously carried a cash award of $1,000 each.

Even more reminiscent of the Oscars are the association's plans for a "gala evening of entertainment, a celebration for the industry, and a news event for the media" at which the winners would be announced. It is hoped that sooner or later one of the major television networks will broadcast the ceremony live a la the Oscars, Grammys, Tonys and Emmys.

Although Esther Margolis, a senior vice president at Bantam and a director of the publishers' association, claims that reaction within the industry has been generally favorable, at least one strong protest has been registered.

Roger W. Straus Jr., president of the independent and illustrious firm of Farrar, Straus & Giroux, is preparing a letter to the association in which he will recapitulate his opinion of the "cheap, horrible, ridiculous, vulgar and pathetic" proposal.

The first round of American Book Awards is scheduled for presentation next spring.