The recruiting institution and orgs now have their own vacation alerts via mail. Besides, RG, Linkedin, Mendeley Careers, and in other career sites. Keeping yourself update is the key.
In my opinion, in Australia, you could find an interesting position through LinkedIn. However, there is more opportunity if you could search on a job search engine such as seek and indeed sites for that specific country. Moreover, Applying through the university cites is the best way for finding research base position. I put some useful links below.