Massachusetts congressman Ed Markey has introduced a bill that aims to guarantee internet neutrality after a similar amendment was voted out at the committee stage last month.

The bill seeks to ensure that internet access charges for websites and applications are all priced on a level playing field.

Telecoms operators have spent hundreds of millions of dollars lobbying for the right to charge extra for faster access to sites and choose what applications they carry.

"The corrosion of historic policies of non-discrimination by the imposition of bottlenecks by broadband network owners endangers economic growth, innovation, job creation and First Amendment freedom of expression on such networks," said Markey as he introduced the bill.

"Broadband network owners should not be able to determine who can and who cannot offer services over broadband networks or over the internet.

"The detrimental effect to the digital economy would be quite severe if such conduct were permitted and became widespread."

The proposed legislation states that a broadband network provider may not block, impair, degrade or discriminate against the ability of any person to use a broadband connection to access the content, applications and services available on broadband networks, including the internet.

Pressure group MoveOn.org has started an online petition for internet users to make their voices heard, and internet neutrality supporters have set up their own website to coordinate the response. 

The SavetheInternet.com Coalition announced that its petition signatures to preserve net neutrality jumped from 250,000 to 500,000 in less than a week.

The number of organisations participating in the coalition jumped from 50 to 400, including groups as diverse as Gun Owners of America and Craig Newmark of Craigslist.

"Without statutory network neutrality, there is nothing to prevent big telecoms companies from injecting political bias into the very skeleton of modern communications," said Craig Fields, director of internet operations at Gun Owners of America.

"Whenever you see people on the left and right joining together about something Congress is getting ready to do, it's been my experience that what Congress is getting ready to do is basically un-American."