G'Day RussellC. I'm an Aussie living in the US, so I can give you some additional info. There is firearm ownership in Oz, but without a 2nd Amendment it is treated as a privilege and not a right.
It is very heavily controlled by the government, with not only each owner needing to be licensed, but also each firearm that owner has. Because of this, each time a new law is passed banning a new type of firearm (there have been two separate occurrences of this over the past 20 years) the police know who the legal owners of the newly banned firarms are, and pay them a visit if the firearms are not surrendered.
A reason needs to be given to the police as to why a firearm needs to be purchased, and self defense is not considered a valid reason. Hunting, vermin control and competitive shooting are the only valid reasons.
Since there is no concept of legal self-manufacture of firearms, such a law could be put in the books and in concept is already there. This bill would only specifically cite 3D printing as a means of manufacture. It's very much a PR ploy to be seen to be responding to a non-existant issue.
If you don't want this kind of policy here in the US, make sure you support groups such as the NRA, even if you don't agree with all their policies. There are groups here who would LOVE to implement the same cr@p.
Cheers!