Australia's minimum wage is $15.51 per hour or $589.30 per week. Generally, employees in the national system shouldn't get less than this.
An employee's basic rate of pay depends on such things as their age, job classification and what industrial instrument they're covered by (e.g. a modern award, pre-modern award, workplace agreement and so on).
An employee may also be entitled to other allowances or loadings, depending on the job they do (eg. a casual employee may be entitled to a casual loading).