The answer, as you would expect from a law firm, is it depends.
If you are a small business with a turnover less than $3 million per year then you do not need to comply unless you fit into one of the following exceptions:
A small business that is otherwise exempt can choose to be covered by The Privacy Act if it wishes.
If you are in any doubt about your obligations feel free to give us a call. It costs nothing to ask and we will be glad to help you comply if you need to