It is important to be clear from the outset whether or not your staff are, in fact, casual.
A staff member who is employed on a regular and systemic basis may be able to claim leave and other entitlements under the National Employment Standards although they have received the casual leave loading. (National Employment Standards provide for annual, personal, compassionate and parental leave.) Where an employee makes a claim, the employer would have to request a court to offset any casual loading amount in lieu of the National Employment Standard entitlements and it would be up to the courts to decide whether the casual loading is to be taken into account in each particular case.
Please contact us if you need more information.