PERTH, Australia - The government-backed mandatory Internet filtering system being implemented in Australia could block upwards of 10,000 sites that feature "unwanted" content, news agencies are reporting.

And residents are unable to completely opt out of the Cyber-Safety Plan. The Cyber-Safety Plan, which was first announced by the Australian government in 2007, was designed to block "illegal" content as well as pornographic material inappropriate for children.

Users only can opt out of the "additional material" blacklist, but not the main blacklist. The additional material blacklist targets content inappropriate for children, while the main blacklist filters any content the Australian government deems "illegal." There were no guidelines presented on what content would be considered illegal, however.

Now, the Courier-Mail reports that the government has deemed as many as 10,000 websites that contain "illegal" content, though what that specific content is was not described.

Communications Minister Senator Conroy told Parliament on Thursday that the filtering system "will specifically test filtering against the [Australian Communications and Media Authority] blacklist of prohibited content, which is mostly child pornography, as well as filtering of other unwanted content."