Global mining giant BHP Billiton said Wednesday it was cooperating with a US probe into its sponsorship of the 2008 Olympics amid reports it used the event to curry favour with Chinese officials.

BHP, the world's largest miner, confirmed media reports that it had been questioned by the US Department of Justice about its support of the Beijing Games, which was described by Australia's Fairfax newspapers as "unusual".

Instead of using the Olympics affiliation to promote its products Fairfax said BHP ran a "behind-the-scenes campaign to improve relations with its most important clients -- those who run China's state-owned steel-making firms".

Chinalco, Baosteel and the China Iron and Steel Association were reportedly among those wooed by BHP during the Olympics, which came at a time when the mining giant was being criticised in the media for high iron ore prices.

The charm offensive had come to the attention of the US Securities Exchange Commission for possible bribery of foreign officials to obtain a business advantage, the Australian Financial Review said.

Anglo-Australian BHP confirmed it had been "cooperating with the relevant authorities in an investigation into possible violations of anti-corruption laws".

"In response to comments in the media about BHP Billiton's sponsorship of the 2008 Beijing Olympics, we believe our Olympics activities complied with all applicable law," a spokeswoman told AFP.

"BHP Billiton is fully committed to operating with integrity and the Group's policies specifically prohibit engaging in bribery in all its forms."

Given it was an ongoing matter she said it would be inappropriate to comment further.

The Australian Federal Police (AFP) confirmed that they had also been involved in the investigation and were "working very closely coordinating activities with our foreign counterparts and local regulatory agencies".

"The AFP has received a referral that relates to the Australian aspects of the US investigation, It would not be appropriate to comment any further on operational matters," it said.