Australia's procurement process is probably going to require a lot of study, negotiation with various potential manufacturers, and involvement with the legislature.
It is not uncommon for a large military project to be awarded to an entity that has shown to the military and legislative body's satisfaction that their proposal is really the only one that makes good military and budgetary sense.
Many times, this is not so clear and a tender will be made for the various companies to make proposals to prove who is the best based on performance, ultimately of their prototypes.
I believe that the Japanese submarine would be the best solution for Australia...but even though technically and militarily that may be the case...there is still the need for it to fit politically. Most politicians will want to do what is right and best (normally...but not always), but will also have that desire influenced heavily by the re-election prospects.
I believe Abbott's comments about Australian shipbuilders was purely political and from that quarter. That type of thing is something that the Japanese or anyone else will have to make allowances for...and try to help with...otherwise, without that consideration...any deal is likely to be stillborn.