It's Vic rules and they're similar to NSW rules. There are no "Australia wide" rules per se (frustratingly).
When SAKSA met with Transport SA, the 400m exemption was proposed but Transport SA's position is simply that pfds are required unless kiters can show that pfds actually pose a threat to safety.
Unfortunately SAKSA still hasn't received any anecdotal evidence of safety issues following the SAKSA newsletter in May or on the SAKSA forum:
http://www.saksa.com.au/forums/viewtopic.php?f=2&t=47 +
www.saksa.com.au/forums/viewtopic.php?f=2&t=301If your personal safety (or the public's safety) has been threatened as a direct result of a pfd, then shoot the details through to info@saksa.com.au
If SAKSA can get enough evidence, then Transport SA will look at it.
Cheers,
Chappy