Having any word, be it of a country or anything in the title, will positively impact the SEO ranking of your website for that term/word.
The title is very important for higher SEO ranking and therefore should be wisely created/chosen and used.
1) It gives a good indication to a crawler (Search Engine like Google) about the content of page/site
2) It showcases in a rich snippet of search results and serves as the entry point for your user. If the content is relevant, the chances of a user clicking your results are higher.
So, if you think that putting Australia in the title would help user reach your site or improves the search result rich snippet in any way, shape or form, then go ahead and use it. Otherwise please ignore and use more relevant words/terms.
While putting a word like Australia or any other country name for that matter may not hurt your SEO ranking, as i already explained, when a user sees Australia, he/she might get a negative impact if user is not from Australia.