According to http://www.dnsbl.com/2009/04/status-of-dnsblnetau-dead.html:
The blacklist at dnsbl.net.au has announced it is winding down. As noted in a February 25, 2009 posting on its website, "Please note that as of Wednesday, April 1, 2009 the DNSBL.NET.AU blacklist will cease to exist."
Is the information on our site wrong or incomplete? You don't want us to monitor your blacklist? Or do you operate a similar blacklist? We would like to hear from you!