Political Science is not a really big area in Australia, generally you will find politics as a whole is very socially unacceptable - the police have to force people to vote in elections, and as such there is very little from you to get from it. As one of the above posters mentioned becoming a teacher is one field that would help you get there although you would require some experience in the United Kingdom and teaching politics would not really be an option as again its not very popular and most educational qualifications do not have a 'Politics' course like in the United Kingdom. The closest you would get is a History/Geography teacher (In Australia, well at least NSW, the two subjects are merged) which covers subjects like 'economics' but that would require doing a lot of bridging courses as the main material is about Australia - e.g. legal issues regarding Aboriginals which you would have to learn first.
Overall I would say that a Masters Degree in Political Science is not really useful in Australia, the one area I could think of (off the top of my head) that it could help you with is if you tried to get a job with one of the big multinational charities that cover issues such as Asylum Seeker rights and advising the Australian Gov't, I know they sometimes try to bring people in from abroad to do work with them. That could give you the opportunity to travel around within Australia and see what things are like.
If you can get a job and get sponsored for permanent residency its a pretty good deal though in the end as you have free movement between New Zealand and some of the Pacific states as well, like in the EU, which could be your thing if your looking to explore.