Thanks, this sound perfect. Exactly what I was looking for. Are you working for them? Do you have a contact to apply directly to?
Our recruitment process for grads and interns is somewhat different and I don't know anything about it, sorry.
Interns were generally from the UNSW corporate placement program (though I can't remember the exact name for it).
Atlassian are a fantastic place to work - if you're in a position to apply for them I would highly recommend it.
Source: used to work there, hosted interns.