I also watched "Fortress Australia", and found what was claimed plausible, especially as there have also been claims Australia took an interest in biological weapons (eg Secretary of the Department of Defense F.G. Sheddon asking  Sir Frank Macfarlane Burnet if Australia could develop biological weapons that'd affect Asia but not Australia). But what has been said here seems like a fairly serious rebuttal. Maybe there should be a wikipedia entry Fortress Australia discussing the allegations in the documentary, and possibly a note in this page to the documentary.