Google has warned that a forthcoming UN-organised conference threatens the "free and open internet".
Government representatives are set to agree a new information and communications treaty in December.
It has been claimed some countries will try to wrest oversight of the net's technical specifications and domain name system from US bodies to an international organisation.
However, the UN has said there would be consensus before any change was agreed.
Google has asked web users to add their name to an online petition to support its view.
"The [UN agency] International Telecommunication Union (ITU) is bringing together regulators from around the world to renegotiate a decades-old communications treaty," it wrote on its Take Action site.
"Some proposals could permit governments to censor legitimate speech - or even allow them to cut off internet access.
"Other proposals would require services like YouTube, Facebook, and Skype to pay new tolls in order to reach people across borders. This could limit access to information - particularly in emerging markets."
Google added that it was concerned that "only governments have a voice at the ITU" and not companies or others who had a stake in the net, concluding that the World Conference on International Telecommunications (Wcit) was "the wrong place" to make decisions about the internet's future.
However, the ITU has said that each country could invite whoever it likes to be part of its delegation at the meeting.
Read more: http://www.bbc.co.uk/news/technology-20429625
