Any owner in the building can pursue complaints about by-law breaches (through the mediation and tribunal system).
NCAT was supposedly set up to be lawyer-free so the default is “no lawyers” although that is changing. If the miscreant hires a lawyer to defend their case, then your strata committee can do the same and claim costs on the basis that the defendant had a hopeless case (if indeed, the breaches are clear and obvious).
Just follow procedure. It’s all written down in the various websites. As a wise person once said, anyone who sacrifices what’s right and just in order to save money, deserves neither.