According to the BBC, the dancers say that despite a recent renovation, the dressing rooms are too small and that higher priority is given to backstage space for orchestra musicians.
The strike will force the cancellation of ten performances of Kenneth McMillan's L'historie de Manon. Sylvie Guillem and Alessandra Ferri were among the dancers scheduled to share the title role.
Short-term industrial actions are relatively common for performing arts unions in Italy seeking to change a policy or simply make a point. Earlier this year, musicians and other workers at La Scala called a strike to protest the firing of general manager Carlo Fontana. The turmoil at the company eventually led to the resignation of music director Riccardo Muti and Fontana's successor, Mauro Meli.