A person does not have the right to not be photographed in Australia; as Australia has no Bill of Rights in the sense that many other countries do, there is no guaranteed right to privacy. However, there is also no guarantee to freedom of speech, except where political discourse (and by extension, the “newsworthy") is concerned.
(The exception is Victoria, where a “Charter of Human Rights and Responsibilities" provides a working equivalent to a Bill of Rights.)
It's not just a free-for-all, however, due to the absence of law. Tight anti-voyeurism, defamation and obscenity laws make photography often difficult to justify, particularly with the “artistic" which often attempts to blur these boundaries. These concerns will trump even occasions when consent by the subject has been given.
Furthermore, just because something is publicly accessible does not mean that you are necessarily allowed to take photographs, as you can in the US. The owner of private property has full control over what actions you are allowed to take while on that land, and that includes photography.
As in the US, no one has any legal right to confiscate your camera without a court order. While violence and coercion against photographers is unfortunately commonplace, it is not justified by the laws and may in fact lead to criminal offenses, perhaps small consolation.
Military instillations again fall under special circumstances: while you may not have your camera permanently taken away, you may still be asked to delete certain photos.
For an extensive discussion Australian photography laws, check out this article by NSW Photographer.