It's looking doubtful. SCEA President Jack Tretton, in a revealing interview with Engadget, stated that the NGP would launch in at "at least one territory" by Christmas 2011 - most likely that region will be Japan or the US, but probably not Australia.
We're remaining hopeful - it could be that Sony are simply being conservative with their estimates. The PS3 launch suffered from delays and setbacks - and part of the initial Sony backlash was the broken promise of a simultaneous worldwide launch. It could be that Sony are being very careful to not bullishly make the same mistake twice. If production can't keep up with demand Sony may have to resort to the staggered PS3-style launch dates, with Europe and Australia hitting early 2012 compared to a US and Japan Christmas release.
It's purely speculation at this point. We're unlikely to have any concrete details on an Australian launch until much later, possibly around E3 this June. Sony's Australian Managing Director Michael Ephraim is currently in Tokyo, but we're currently chasing more info and will hopefully get the chance to quiz him on any prospective price and release date soon.