Sites featured on the list were only revealed this month after a leaked version was published on the Wikileaks website. While the list of "prohibited" material does not have a significant impact on most internet users today, links contained on it will be blocked for everyone if Conroy proceeds with his mandatory internet filtering plan.

Henson's spokeswoman Sue Cato declined to comment, as did ACMA and Conroy. Colin Jacobs, spokesman for online users lobby group Electronic Frontiers Australia, said: "With an abortion site, the Peaceful Pill Handbook and Bill Henson photos all now revealed to be on the blacklist, claims that the list only includes the 'worst of the worst' of the web are sounding like those over-emphatic defences of Guantanamo Bay." Jacobs said EFA was "pretty unenthusiastic" about a censorship system "where we have no choice but to take such assertions at face value".

Greens Senator Scott Ludlam said: "It's a classic example of that scope creep. They say it's about the worst of the worst but before you know it it's expanding to cover other kinds of material."

The Classification Board said it had received 10 applications to classify works by Henson. It found the images of children were not sexualised, "mild in viewing impact and justified by context". This is despite some of the images depicting a naked female with "breast nudity".

Henson's images sparked a political storm last year following an uproar on talkback radio, which led to police seizing 32 of Henson's photographs from Sydney's Roslyn Oxley9 gallery. At the time, the Prime Minister, Kevin Rudd, declared the pictures "absolutely revolting". But the case against Henson eventually collapsed, with the Director of Public Prosecutions advising NSW Police that any prosecution of Henson would be unlikely to succeed. Conroy initially called into question the veracity of the leaked blacklist but yesterday said the latest leaked version, dated March 18, "seemed to be close" to ACMA's current blacklist.

"It is completely untrue that the leaked blacklist contains political content. This is a list which contains sites that promote incest, rape, child pornography and child abuse," he said. However, alongside child porn, bestiality, rape and extreme violence sites, the leaked list also includes a slew of online poker and gambling sites, YouTube links, regular gay and straight porn sites, Wikipedia entries, euthanasia sites, websites of fringe religions such as satanic sites, fetish sites, Christian sites, the website of a tour operator and even the sites of a Queensland dentist, a school canteen consultancy and an animal carer.

"If in the future the Prime Minister finds a controversial artwork 'revolting' or an online game too violent, do you trust him to resist pushing the 'ban it' button? He could then go on talk radio and say something was being done," Jacobs said. The Opposition communications spokesman, Nick Minchin, said he had not seen the blacklisted link with the Henson images but the revelations raised "further questions about how Senator Conroy will compile any blacklist and how this will be vulnerable to 'creeping' based on the political will of the day". Yesterday, Conroy said public concern about the possibility of the blacklist "creeping" to include legal content was justified, but stopped short of guaranteeing the Government would be able to prevent it.

The Government plans to expand the blacklist to up to 10,000 sites and has said it plans to incorporate sites found on international blacklists.