US lawmakers have dealt the concept of net neutrality a crushing blow just two weeks after a rival US government committee seemed to give it the green light.

Two legislative proposals are going through the US Congress, with Democrats largely backing net neutrality and Republicans largely keen to leave regulation to the market and decisions in the hands of telecommunications firms.

Two weeks ago a House of Representatives Judiciary Committee backed the Internet Freedom and Nondiscrimination Act, which proposes enshrining in law the principle that telecoms firms cannot block or charge for internet services at will.

Meanwhile a competing Bill is being processed, the Communications Opportunity, Promotion and Enhancement Act (COPE), to which an amendment to the same effect was proposed. That amendment was defeated in the House, meaning that the two acts are now in opposition.

The vote, argued the amendment's proposer Representative Ed Markey, would change "the internet for the rest of eternity. The future Sergey Brins, the future marc Andreessens, of Netscape and Google, are going to have to pay taxes" to broadband providers, he argued.

Telecoms companies have argued that they should be paid extra in order to deliver the services that make money from being connected to users' homes. The move has been opposed by those companies, such as eBay, Google and Yahoo.

The passing of the bill raises the prospect that US telecoms firms could charge internet companies a premium for access to consumers.

The telcos argue that they have paid for the infrastructure, not the internet companies, so the internet companies should not be allowed to profit from that infrastructure for free.

The internet companies and other advocates of net neutrality argue that consumers pay telcos to connect them to the entire internet, not just those who in turn pay the telcos.

The COPE Act will now progress to the Senate. If it is approved there without amendment and is signed by the US President then it will become law.

The other proposed bill, the Internet Freedom and Nondiscrimination Act, still awaits a floor vote in the House of Representatives.