I think you can ...
Hi KCR,
I am in the position as you are, PR of Oz, waiting on my GC from Nebraska. I would 'guess' (get a 2nd opinion, please) that as long as your PR is valid, or there would not be an issue renewing your PR then you should be fine. My meaning behind the PR renewal is this ... If you have spent more than 5 yrs away from Oz (again this may have changed) - you should be ok to renew. If you have family ties to Oz - all the better.
KCR - I would urge you to consult an Oz attorney on this ...
Hope this helps ...