Definitely, and for several reasons.
First, there is currently a legal vacuum with respect to this type of personal information held by politicians' offices and political parties.
I've read this committee's previous studies. You discussed the question of whether political parties should be subject to the Privacy Act. I won't get into that, because it's not the subject of your question.
To answer your question, I would say that it would fill in a legal gap if ministers' offices were made subject to the Act. When a party is in power, it becomes the manager of the state, and exercises state powers. It should therefore be accountable for compliance with fundamental rights and for the constitutionality of state action.
If the Privacy Act were extended to ministers' offices and the Prime Minister's office, it would, indeed, be a positive development.