An Australian government proposal for a mandatory web filter has been criticised by key internet players Google and Yahoo as a heavy-handed measure that could restrict access to legal information. The government says the aim of the filter is to block access to sites with material that include child pornography, sexual violence and “detailed instruction in crime”. But advocates of free information are concerned that compulsory screening could eventually grow to bar other controversial but otherwise legal material. The statements from Google and Yahoo were among 174 submissions sent to the Australian Department of Communications as part of a public consultation exercise on the proposed filter. Stephen Conroy, the Australian communications minister, said the views would be considered before the final draft goes to parliament later this year. Conroy has previously said he wants the filter introduced to bring the online world in line with censorship standards applied in Australia to material such as films, books and DVDs. The Australian plan was criticised earlier this month by media rights watchdog Reporters Without Borders (RSF), which said the proposed filter would hurt free speech. As a result RST placed Australia on its list of countries under surveillance in its annual “Internet Enemies” report on online freedoms.