The US has passed child safety legislation that could widen the Federal Communications Commission's (FCC) powers to include the internet, according to constitutional campaigners.

The Child Safe Viewing Act of 2007 (S.602) was passed by the Senate Commerce Committee and requires the FCC to do a study of internet filtering technologies.

The research will include the "existence and availability" of filtering technologies for audio and video content transmitted over "wired, wireless, and internet" platforms, as well as other devices.

A statement from the Center for Democracy and Technology (CDT) said it did not oppose a purely fact-finding study, but maintained that a neutral, non-regulatory body such as the National Academy of Sciences would be better suited to the project.

"More importantly, CDT is concerned that this legislation may represent a step toward expanding the FCC's censorship authority to include internet content," the CDT statement said.

Adam Thierer of the Technology Liberation Front praised the legislation for empowering families to make their own media consumption decisions.

However, he agreed that the bill could widen the FCC's powers.

"Unfortunately, the measure seeks to accomplish that goal through government actions that could have potentially troubling regulatory implications, especially because of the First Amendment issues at stake here," he added.

"Specifically, S.602 opens the door to an expansion of the FCC’s authority over media content on multiple platforms and threatens to undermine private, voluntary rating systems in the process."