A Halliburton subsidiary that has been awarded billions of dollars in federal contracts in Iraq has been accused by an independent watchdog of “abuse” of government regulations that protect US taxpayers.

Stuart Bowen, the special inspector-general for Iraq reconstruction, said in an interim audit released on Thursday that Halliburton subsidiary Kellogg, Brown and Root (KBR) had, in effect, routinely inappropriately hidden data about one of its contracts from public scrutiny by marking the information as “proprietary”.