As Google takes its first defiant stand against a Chinese regime determined to block its search engines from accessing restricted content, the web monolith now seems set to fight the federal government here on its plans for an internet blacklist.

Google will challenge communications minister Stephen Conroy on the effectiveness of the planned filter and his claims that it won’t impact web browsing speed, the company has told Crikey. A submission will be put to the government next month.

In China, Google willingly censors content to operate under the communist regime — a practice it now wants to review in the wake of last week’s email hacking scandal. Under the Australian plan, restricted content will be blocked at the ISP level — whether Google’s crawlers find it or not. The web giant is “concerned”.

“Google Australia and worldwide is obviously watching the government’s filtering regime proposal very closely,” a spokesperson said. “Our current plan is to look more closely at the technical feasibility of filtering. We’ll be participating in the debate on filtering in the coming weeks and months. If passed, we will look at the details of any legislation.”

Google will argue the scope of content proposed to be filtered is too wide. In a blog post written in December, Australian policy head Iarla Flynn branded mandatory ISP-level filtering “the first of its kind amongst Western democracies” and “heavy handed”. Flynn wrote:

Some limits, like child pornography, are obvious. No Australian wants that to be available — and we agree. Google, like many other internet companies, has a global, all-product ban against child sexual abuse material and we filter out this content from our search results. But moving to a mandatory ISP filtering regime with a scope that goes well beyond such material is heavy handed and can raise genuine questions about restrictions on access to information.

Flynn says the Australian filter would be unique as a mandatory framework. Germany and Italy have mandatory ISP filtering but for a limited range of sites (child-abuse material, and in Italy unlawful gambling sites).

Google told Crikey it wants “more light shed” on the technical trials, to which it wasn’t party. It’s particularly concerned about the “potential impact on speed”.

“The government’s own technical report states that someone with competent technical expertise could probably get around it. Filtering should only be seen as one part of any effort towards protecting people’s online experience. We believe that education and police enforcement is vitally important,” the spokesperson said.

Conroy is standing by the pilot program, conducted by independent company Enex TestLab. His office told Crikey it demonstrates a filter can be applied with “negligible impact on internet speed”.

“Telstra undertook its own testing that showed the impact on internet performance would be 70 times less than the blink of an eye. This is consistent with the findings of a pilot of ISP-level filtering in New Zealand and the experience over many years of ISPs in a number of Western democracies including the United Kingdom and Canada,” a spokesperson said.

As for division within Labor on the plan (Crikey reported last week  back-bench Senator Kate Lundy is pushing for an “opt-out” alternative), Conroy simply says the legislation will be “considered” by caucus. Lundy lamented she believes a mandatory filter has majority support within the party.