Internet giants Google and Yahoo have criticised Australia's proposal to introduce a mandatory internet filter, calling it a heavy-handed measure that could restrict access to legal information.
Their statements were among 174 submissions to the Australian Department of Communications related to the filtering policy.
Communications Minister Stephen Conroy, who made the submissions public yesterday, has explained the filter would block access to sites that include child pornography, sexual violence and detailed instruction in crime.
Adopting a mandatory screening system would make Australia one of the strictest Internet regulators among the world's democracies, and the proposal has put the country on the Reporters Without Borders annual "Enemies of the Internet" list.
"Our primary concern is that the scope of content to be filtered is too wide," Google wrote in its submission, also suggesting the filter would slow browsing speeds.
The company said it already had its own filter to block child pornography.
"Some limits, like child pornography, are obvious. No Australian wants that to be available - and we agree," the Google submission said. "But moving to a mandatory ISP level 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."
Lucinda Barlow of Google Australia said today that Australia's proposal went beyond filters used in Germany and Canada, which block child pornography and, in Italy, gambling sites.
"This enters the gray realms of restricted classification, seeking to ban politically and socially controversial material," Ms Barlow told Australian Broadcasting Corp.
Yahoo's submission struck a similar note, saying the filter would block many sites that contain controversial information - such as euthanasia discussion forums, safe injection information, or gay and lesbian forums that discuss sexual experiences.
"There is enormous value in this content being available to encourage debate and inform opinion," Yahoo's submission said.
The filter would not block peer-to-peer file sharing nor prevent predators approaching children in chat programs or social-networking sites, and both Google and Yahoo backed a national campaign to educate parents and children about safe use of the Internet.
Other submissions came from Australian telecommunication companies, lobby groups and many individuals.
Mr Conroy said his department would consider the submissions before sending the final proposal to Parliament later this year.
"A range of views have been expressed in the submissions and I would like to thank everyone who contributed their comments and valuable ideas to the public consultation process," Conroy said in a statement. "(We will) examine whether the ideas can be used to enhance the proposed accountability and transparency measures."