In Australia, deductions from wages must comply with the Fair Work Act 2009 and the relevant Modern Award or Enterprise Agreement covering your employment. Employers can only deduct wages if there is a lawful basis for doing so, such as if you’ve agreed to the deduction in writing or if it is allowed under your employment contract or another enforceable agreement.

Deductions for mobile phone use might not be justifiable, particularly if you were using your phone during quiet times when it didn’t disrupt your work responsibilities or affect customers. It may be considered an unreasonable deduction since using a personal mobile phone during a lull doesn’t directly relate to the performance of your role.

You might consider discussing the matter with your employer to understand their rationale for the deduction. If you feel the deduction is unfair or against the law, you can seek advice from the Fair Work Ombudsman or your union (if applicable). They can provide further guidance and support your rights as an employee.