No amount of new casting can alter the contours of so massive a production as "Spartacus," but the dedicated energy with which the Australian Ballet tried during the weekend to bring life to Hungarian choreographer Laszlo Seregi's conception of ancient Rome is one of the company's attributes as well as one of its limitations. A wickedly campy redirection of the entire spectacle might have done it, but for that Maina Gielgud and her dancers are too honest.

Following the work's Kennedy Center premiere Friday, there were changes in the three major roles as well as in some subsidiary ones. For this viewer, though, Australian sincerity and effort were personified by a dancer not relieved of his part during this piece's four-performance run. Ricardo Ella, as the longest survivor among Spartacus's slave gladiator companions, poured himself into two hours' worth of fighting and suffering with such freshness and fervor on each occasion that one longs to see him tackle a principal part.

The only performer to elicit sympathy as Spartacus, leader of the slave revolt, was Greg Horsman. He'd been consistently super-civilized as Crassus, the Roman commander and chief adversary to Steven Heathcote's barbarian Spartacus on Friday, but in the title role Saturday night he didn't convey a unified characterization. Crucified at the beginning and end of the ballet, his features expressed mystic passion and resignation. In other scenes, he was warmly human in responding to his friends and wife. These traits weren't linked, and no particular characterization informed Spartacus's many passages of action. Dancing, though, Horsman was the only one to make some dynamic sense of the hero's solos, giving them lyric sweep.

Gyorgy Szakaly, a guest from choreographer Seregi's own company at the Hungarian State Opera in Budapest, acted Spartacus in the Central European expressionist manner and danced on a big Soviet scale at Saturday's matinee. Cadaverous on the cross, and sullenly angry at other times, Szakaly made the slaves' leader hideous in every detail -- even in his makeup. His dancing covered the stage in great arcs of movement and he reached the top of an imprisoning grid in a single leap. Yet, a hint of stiffness and excessive preparations suggested we were seeing a principal past his peak.

David Ashmole, whose Duke of Windsor visage seemed apt for an upper-class Roman, was Crassus at both Saturday performances. He acted well in the afternoon, distinguishing between the cold public figure and the playful private man. At night, Ashmole was in good dancing form, giving Horsman more competition than he had Szakaly. At the Saturday matinee, Fiona Tonkin's smoothness and warmth made Spartacus's wife a loving, perhaps too matronly figure. Also that afternoon, Anna de Cardi was the principal courtesan in Crassus's entourage and got more fun out of the part than other dancers. The Las Vegas number she performs with four boys is this ballet's only piece of trash worthy of becoming a collector's item.

Otherwise, Seregi has made the mistakes of trying to be serious and subtle on an epic scale. The staging (which rearranges Khachaturian's music) shows a modern-dance rather than balletic sensibility, though not one that is developed choreographically. Some movement themes are eye-catching, such as the slaves marching on their knees, but generally Seregi is better at devising pas de duels than pas de deux and other balletic passages.

Saturday at 6 p.m. at a symposium onstage at the Opera House, Australian Ballet director Gielgud answered questions fielded by National Public Radio's Kim Kokich and showed off young company dancers in bravura passages from the repertory. Good bodies, often tall and ample, and promising performances were apparent throughout. Particularly impressive were Olivia Woodland's finely laced footwork in a "Giselle" solo; Bernadette Ceravolo's passion in the bedchamber duet from Cranko's "Romeo and Juliet"; excerpts from Lifar's "Suite en Blanc" with Justine Summers, Andrew Murphy, Adrian Burnett and Michele Goullet; and the firecracker Campbell McKenzie in a "Don Quixote" solo. Gielgud, asked about an "Australian" style, answered that this is something that can't be imposed but will have to evolve. Glimmerings may be there already.