The distributed denial of service attacks, reported by the Herald Sun, crippled Australia's parliamentary website as well as its communications unit.
The attacks were launched by hackers known as "Anonymous."
"No government should have the right to refuse its citizens access to information solely because they perceive it to be 'unwanted'," the group said in an email. "The Australian government will learn that one does not mess with our porn."
Fiona Patten of the Australian Sex Party told XBIZ in December that the filter would block 95 percent of adult websites and slow down the web dramatically.
"How your can have a filter blocking access to more than 4 million sites with more than 420 million pages and not slow the Internet down is beyond belief," she said.
Porn censorship in Australia recently has been ramped up, according to Patten.
Just last month, Patten alleged that government censors are directing customs officials to confiscate media where depictions of the female orgasm is accompanied with an ejaculation.
She also complained that some adult videos recently have been rejected by censors because they starred small-breasted women who could be confused as minors and appear underaged.
“We are starting to see depictions of women in their late 20s being banned because they have an A-cup size,” she said.
According to Fiona, the dDOS campaign, dubbed "Operation Titstorm" by its creators, appeared to spring from last month's Sex Party's comments on pornographic censorship of A-cup-sized women.