The Metropolitan Opera moved into high gear last night in the Kennedy Center when it unveiled its new production of Verdi's "La Traviata."

Elegant sets and lighting provided an ideal background for the familiar drama. A new conductor, Thomas Fulton, kept a strict hand on the music, moving it as rapidly as it could possibly go, even to the point of eliminating certain desirable broadenings that heighten Verdi's glorious writing. But within his rather inflexible conception, he held things firmly under control.

Catherine Malfitano has added notably to the fine realization of the title role she gave here several seasons ago. Her voice responds fully to every demand placed on it, so that the coloratura in the first act was skillfully encompassed, while the tragic pathos of the succeeding acts was movingly projected. She could make her portrait even more toughing by greater use earlier in the opera of the exquiste floating tones she displayed in the final act. A consummate actress, she should rethink the death scene. In its protracted extensions her actions become excessively frantic.

Tender David Rendall stepped into the role of Alfredo because of the indisposition of Giuliano Ciannella. His voice, which has a very rapid beat, is a bit light for the part, but he uses it in musicianly fashion. That he seemed ill at ease in the earlier scenes is entirely understandable. By far his most effective work came in the extremely sympathetic singing and acting he contributed to the last act.

Sherrill Milnes is a tower of strength in any opera. He has polished the art of the Verdi baritone to a rare luster, singing Germont with magnificent style, flawless enunciation, and, beyond all this an awarness of every nuance in the part. Whenever he was on the stage, it was impossible not to sense the presence of one of the great artists of our time.

The third act party scene in Flora's house had just the right touches of garish opulence, so that the rowdy behavior of the guests seemed entirely reasonable. But the staging of the opening gyspy chorus has rarely looked more vapid and Zachary Solv's following ballet was a feeble effort. The Met and other companies have done it much better.

This seems to be the season of new heights in the department of throwing things on the floor. Last night red camellias went first, followed by bills, letters, a blanket, a cape, another letter and white camellias. (At the Met's opening night of "Manon" Monday, it was jewelry, a dress and a cape.) Come on, fellows, how about now and then just putting things down on a table or chair?

There were again outstanding artists in the miniature roles that give "Traviata" its peculiar richness: Julien Robbins' Marquis and a Letorieres of particular sympathy in acting from Dana Talley.

The chorus was excellent in sound, though often rather routine in movement.