I think the devil is in the details. What do you have to show you were temporarily overseas? Did you have permanent residency in Australia, or a temporary work visa? etc, etc.
For example my son applied to universities in the UK. On one of the forms (to determine residency) they stated that in order to prove that the time overseas was temporary they needed: "A letter from the employer of the person concerned confirming that the employment was temporary (eg. contract/secondment) and any other evidence that shows that you are/were only temporarily resident in the overseas country."
So I would imagine that bottom line comes down to what you have to show your residence overseas was only temporary.
There's a thread here
on this topic that you may find useful.