BHP Billiton is facing possible corruption action by US regulators stemming from the Beijing Olympics and an investigation.
The US Securities and Exchange Commission (SEC) and Department of Justice have told the resources giant it is facing enforcement actions.
BHP, the world's largest miner, is the subject of bribery-related allegations through its sponsorship of the 2008 Olympics.
The claims involve hospitality and gifts given to Chinese dignitaries, including steel company representatives, to woo them during the Games.
It is understood BHP's involvement in trying to secure the rights to develop a bauxite project in Cambodia in 2006 is among some mining projects being investigated by the regulators.
The Australian Federal Police are also part of the investigation.
BHP will not confirm which of its activities, nor in what countries, are being investigated other than the Olympics.
On Friday, it said the issues relate primarily to matters in connection with previously-terminated exploration and development efforts, as well as hospitality provided as part of the company's sponsorship of the 2008 Beijing Olympics.
Possible charges relate to the US Foreign Corrupt Practices Act, with the company subject to US corporate laws through its New York stock exchange listing.
BHP conducted an internal investigation in 2010 and told US regulators it had found evidence "regarding possible violations of applicable anti-corruption laws involving interactions with foreign government officials".
On Friday, it said it was co-operating fully with the relevant authorities.
"BHP Billiton is fully committed to operating with integrity and the group's policies specifically prohibit engaging in unethical conduct," it said.
"BHP Billiton has what it considers to be a world class anti-corruption compliance program."
BHP shares were down 45 cents at $36.88 at 1340 AEST on Friday.
