AUSTRALIA'S mandatory net filter is being primed to block 10,000 websites as part of a blacklist of unspecified "unwanted content".

Some 1300 websites have already been identified by the Australian Communications and Media Authority.

Communications Minister Senator Conroy revealed details of the Rudd Government's proposed web filter as he called for expressions of interest from internet service providers (ISPs) for a live trial of the technology, the Courier-Mail reports.

ISPs will test ways to filter the web using volunteer subscribers. The trial will start before Christmas and is expected to last six weeks.

"The pilot will specifically test filtering against the ACMA blacklist of prohibited content, which is mostly child pornography, as well as filtering of other unwanted content," Senator Conroy told Parliament today.

"While the ACMA blacklist is currently around 1300 URLs, the pilot will test against this list - as well as filtering for a range of URLs to around 10,000 - so that the impacts on network performance of a larger blacklist can be examined."

A spokesman for Mr Conroy later said: ''The pilot will provide an invaluable opportunity for ISPs to inform the Government’s approach.

''The live pilot will provide valuable real-world evidence of the potential impact on internet speeds and costs to industry and will help ensure we implement a filtering solution that is efficient, effective and easy for Australian families to use.''

An ACMA trial of web-filtering technology this year found it could slow internet access by as much as 87 per cent and by at least 2 per cent.

Electronic Frontiers Australia board member Colin Jacobs said his civil liberties group was concerned at what would be deemed "unwanted content".

"It is unclear how ACMA will scale up their blacklist to 10,000 websites and what will go on the list," he said.

"Conroy said the list would contain illegal and unwanted content but we still have to see what would end up on that list.

"Under the current mandate that includes adult material, which would mean most material that could be rated R and, in some circumstances, material rated MA15+."

Source: news.com.au