In Australia there is no minimum working age across all states and territories. The minimum working age depends on the state or territory in which the employee is working.
In ACT and NT there is no minimum age, although workers under 15 years are limited as to the type of work they can do.
In NSW there is no minimum age.
In Qld and Victoria you can work over the age of 15 years, under the age of 15 years you can work in some situations.
In Tasmania there is no minimum age.
In WA you can work over the age of 15 years, under the age of 15 years you can work for certain hours.