when building links for australian sites do the backlinks need to be from australian sites to rank well in google-com-au? ie/ would i be able to achieve good rankings if most of my links were from sites out of australia? does it make a difference at all?
When using google-com-au are most of the SE results a com.au? If the answer is yes, then I'd suspect that those would be the prime sites. If the results are mainly .com sites, then I'd suspect it would not really matter. Though, I'd assume that relevance would be key in link building, regardless of domain extension.
Yes, relevancy is the most important thing for ranking high in regional serach engines, and the anchor text you use for the incoming links. I've worked for a clients site which was specific to Dublin, Ireland but has a .com domain. Most of the backlinks obtained for the site were from .com domains with the main Keywords used in the anchor text. The site automatically started showing on Google.ie and other regional search engines. I'd suggest that you also get links from some .au domains, that might speed up the process.