Unlike the typical American citizen, most US corporations and foreign companies doing business in the United States pay no federal income tax, according to a new report from Congress.

The study by the Government Accountability Office said two-thirds of US corporations paid no federal income taxes between 1998 and 2005, and about 68 per cent of foreign companies doing business in the US avoided corporate taxes over the same period.

Collectively, the companies reported trillions of dollars in sales, according to GAO's estimate.

"It's shameful that so many corporations make big profits and pay nothing to support our country,'' said Senator Byron Dorgan, who asked for the GAO study with fellow Democratic Senator Carl Levin.

An outside tax expert, Chris Edwards of the libertarian Cato Institute in Washington, said increasing numbers of limited liability corporations and so-called 'S' corporations pay taxes under individual tax codes.

''Half of all business income in the United States now ends up going through the individual tax code,'' Edwards said.