It is optional to become an Australian Citizen (when you qualify for it) and permanent residents are not required to become citizens. As a permanent residence visa holder you can live in Australia indefinitely, though you will have to apply for a residence return visa if you want to travel outside Australia once your permanent residence visa has expired. Most permanent residents can spend a maximum of 12 months away from Australia without having to go through the permanent residence visa application process all over again if you cannot obtain an extension of your permanent residence visa.
As a permanent resident you can enjoy all the same privileges that an Australian citizen does, though you cannot vote in state or federal elections or referendums, you cannot apply for an Australian passport and cannot be called upon to complete jury or military service.
As an Australian citizen you can leave and re-enter Australia freely on an Australian passport, vote in state and federal elections and referendums. You can apply for work in the Australian Defence Force or Australian Public Service and can seek election to parliament. You also have access to Australian diplomatic assistance when you are travelling overseas and can register children born outside Australia as Australian citizens by descent.
Warning: Citizens of some countries can lose their citizenship of that country by becoming an Australian citizen, please check with your other country of citizenship’s consulate, embassy or home office to understand if this will affect you or what steps you need to take to maintain your other citizenship (if you wish to do so) before applying for Australian citizenship.
For information on qualifying for Australian citizenship and the relevant links to the Department of Immigration and Border Protection’s website, please see the Australian Citizenship heading under the Deciding to Move heading. You can also Click This Link to go directly to the DIPB Citizenship Web Page.