COMMUNICATIONS Minister Stephen Conroy concedes greater oversight of which websites will be banned under the Government's mandatory internet filter is needed but has ruled out making the list public.

The Federal Government plans to introduce a filter aimed at blocking access to illegal material such as child pornography or content refused classification (RC) by the Australian Communications and Media Authority.

But the blacklist put together by the communications watchdog has not been made public, raising concerns that governments can impose censorship without proper oversight.

Senator Conroy today conceded greater transparency was needed in terms of what was deemed RC material.

"We have a discussion paper that we've issued calling for increased transparency measures," he said.

The measures were needed to make sure governments could not slip things onto the list, he said.

However, Senator Conroy said making the list public would undermine what the internet filter policy was designed to achieve.

"Out of all the issues in the filter (policy) this is the one that's caused me the most thought because a URL address is just that, it's an address," he told ABC Radio tonight.

"When you publish a list of titles of books that are banned, or movies that are banned, you don't give access to the materials by producing that list.

"The problem when you produce a list of URLs is you are actually giving the address of where to go and look."

Some of the world's largest providers of internet services, including Google and Yahoo, have criticised the Government's plans to introduce a filter, describing the move as heavy-handed.

Google said last week that while protecting the free exchange of ideas and information could not be without some limits, people should retain the right to freedom of expression.

The US administration has also raised concerns about the plan.

A State Department official has reportedly said it was contrary to US foreign policy of encouraging open internet access and the spread of economic growth and global security.

