People attend a workshop
People attend a workshop in Madrid in this April 20, 2009 file photo. REUTERS

(Reuters) -- The lawmaker behind a bill to combat online piracy vowed on Thursday to press ahead in the face of fierce criticism from Internet giants such as Google and Facebook.

It is amazing to me that the opponents apparently don't want to protect American consumers and businesses, Rep, Lamar Smith, R-Texas, told Reuters in a telephone interview.

Are they somehow benefitting by directing customers to these foreign Web sites? Do they profit from selling advertising to these foreign Web sites? And if they do, they need to be stopped. And I don't mind taking that on.

The Stop Online Piracy Act, which is before the House Judiciary Committee chaired by Smith, aims to fight online piracy of pharmaceuticals, music and other consumer products by allowing the Department of Justice to seek federal court injunctions against foreign-based websites.

Smith said Internet counterfeiters cost American consumers, businesses, inventors and workers some $100 billion a year, though critics accuse him of exaggerating.

Under the bill, if a judge agrees that sites offer material that violates U.S. copyright laws, Internet service providers could be required to block access to foreign sites and U.S. online ad networks could be required to stop ads and search engines barred from directly linking to them.

Heavyweights such as Google, Twitter, Facebook, and Reddit oppose the bill, which came under fire at this week's Consumer Electronics Show in Las Vegas.

Reddit chief executive Alexis Ohanian has said SOPA would cripple the Internet and pledged to take his social media site dark for one day next week to protest the bill.

This could potentially obliterate the entire tech industry - a job-creating industry, Ohanian wrote on his blog.

Smith stressed the bill would only affect Web sites based outside the United States and criticized opponents for failing to cite specific sections, saying many have failed to read it and were disguising their economic interests with rhetoric about Internet freedom.

Google Executive Chairman Eric Schmidt told the Economic Club of Washington last month that the bill would effectively break the Internet and he compared Smith's efforts to the same type of censorship that Google has experienced in China.

There are some companies like Google that make money by directing consumers to these illegal websites, Smith said. So I don't think they have any real credibility to complain even though they are the primary opponent.

Smith has received numerous awards from conservative organizations for his opposition to efforts to expand the federal government's power.

But the Texas representative says giving Washington sweeping powers over the Internet is necessary to protect free enterprise.

Smith predicted the bill would pass the House. It was about halfway through the process of committee hearings and could go to the House floor in a matter a weeks, he said. The Senate was considering a similar measure.

(Editing by Daniel Trotta and Xavier Briand)