The Communications Minister, Stephen Conroy, has consistently ignored advice from a host of technical experts saying the filters would slow the internet, block legitimate sites, be easily bypassed and fall short of capturing all of the nasty content available online. Despite this, he is pushing ahead with trials of the scheme using six ISPs - Primus, Tech 2U, Webshield, OMNIconnect, Netforce and Highway 1.

But even the trials have been heavily discredited, with experts saying the lack of involvement from the three largest ISPs, Telstra, Optus and iiNet, means the trials will not provide much useful data on the effects of internet filtering in the real-world. Senator Conroy originally pitched the filters as a way to block child porn but - as ISPs, technical experts and many web users feared - the targets have been broadened significantly since then. ACMA's secret blacklist, which will form the basis of the mandatory censorship regime, contains 1370 sites, only 674 of which relate to depictions of children under 18. A significant portion - 506 sites - would be classified R18+ and X18+, which is legal to view but would be blocked for everyone under the proposal.

This week Senator Conroy said there was "a very strong case for blocking" other legal content that has been "refused classification". According to the classification code, this includes sites depicting drug use, crime, sex, cruelty, violence or "revolting and abhorrent phenomena" that "offend against the standards of morality". And last month, ACMA added an anti-abortion website to its blacklist because it showed photographs of what appears to be aborted foetuses. The Government has said it was considering expanding the blacklist to 10,000 sites and beyond.

Xenophon said instead of implementing a blanket mandatory censorship regime the Government should instead put the money towards educating parents on how to supervise their kids online and tackling "pedophiles through cracking open those peer-to-peer groups". Technical experts have said the filters proposed by the Government would do nothing to block child porn being transferred on encrypted peer-to-peer networks. "I'm very skeptical that the Government is going down the best path on this," said Xenophon.

"I commend their intentions but I think the implementation of this could almost be counter-productive and I think the money could be better spent." The policy has attracted opposition from online consumers, lobby groups, ISPs, network administrators, some children's welfare groups, the Opposition, the Greens, NSW Young Labor and even the conservative Liberal senator Cory Bernardi, who famously tried to censor the chef Gordon Ramsay's swearing on television.

This week, a national telephone poll of 1100 people, conducted by Galaxy and commissioned by online activist group GetUp, found that only 5 per cent of Australians want ISPs to be responsible for protecting children online and only 4 per cent want Government to have this responsibility. A recent survey by Netspace of 10,000 of the ISP's customers found 61 per cent strongly opposed mandatory internet filtering with only 6.3 per cent strongly agreeing with the policy. An expert report, handed to the Government last February but kept secret until December after it was uncovered by the Herald, concluded the proposed scheme was fundamentally flawed.

Even Labor has previously opposed ISP-level internet filtering when the Howard Government raised it as a method for protecting kids online. "Unfortunately, such a short memory regarding the debate in 1999 about internet content has led the coalition to already offer support for greater censorship by actively considering proposals for unworkable, quick fixes that involve filtering the internet at the ISP level," Labor Senator Kate Lundy said in 2003.