When Washington-based composer Patrick Kavanaugh offers a new work, one expects a certain unconventionality, not only in the music itself but also in its setting.

In the past, he has tapped into the gospels according to avant-garde pioneers Karlheinz Stockhausen and John Cage. His "The Art of the Maze," for electronic and percussion instruments, uses an intricate form-scheme, allowing the performer numerous options and detours through the score's complicated design. Sports and music--in the form of a billiards champion and a woodwind sextet--form a players' union of sorts in "On Felt," from his ambitious "Music of the Spheres" trilogy.

The world premiere of Kavanaugh's one-act opera "The Last Supper" at the Folger Theatre last evening, while less visibly innovative than some of his previous efforts, was nevertheless impressive for its healthy contemporary insight into Christian faith.

Although scarcely an hour long, the work exhibits several interesting traits. Jesus, the principal role, never sings, though he is repeatedly addressed by the sung entreaties of the apostles; against his spoken monologues, a chamber orchestra of 18 instrumentalists (visible on stage and representing the outside world) provides musical comments.

With Kavanaugh at the podium, the music, a rich blending of dense and airy textures, suited the text admirably, at times a bit too well. Overwrought tuttis prior to the Holy Sacrament, driven home by the relentless bells, all but telegraphed that a scene of extreme gravity was on the horizon. And with the bulk of the lyrical duties assigned to Christ, there were moments when his lines had to be exaggerated to be heard over the din.

William Jeschke as Christ appeared tentative at first, with a nervous smile undermining his words. Yet midway through the production, his self-assurance became the one dramatic constant. Robert Petillo and Michael Blaney as, respectively, Simon Peter and Philip, were standout disciples with their strong tenor voices.

There was no large banquet table, no histrionics and a pastoral set taken from the Folger's presentation of "The Wind in the Willows" for this Last Supper. In spite of a few rough spots, Kavanaugh's interpretation adds a new, laudable chapter to religion in opera.