Rio Tinto said it would cooperate fully with the investigation
An Australian Rio Tinto executive has been arrested and accused by Chinese authorities of spying, the Australian government has said.
Stern Hu has been detained along with three Chinese individuals working for the mining firm.
Australian Foreign Minister Stephen Smith said Mr Hu was suspected of "espionage and stealing state secrets".
Rio Tinto said it would cooperate fully with any Chinese probe and is seeking clarification on what has happened.
The firm has not identified the four workers, but Mr Hu and his Chinese colleagues are believed to belong to Rio Tinto's iron ore sales team.
Rio Tinto spokesperson Ian Head said the firm had not been able to contact the employees.
"Rio Tinto is concerned about the employees' well-being and is doing everything possible to help them and support their families," he said.
The development comes as Rio Tinto is leading price talks for global iron ore suppliers with Chinese mills.
Last month, Rio Tinto pulled out of deal with Chinalco which would have seen the Chinese state-run firm invest $19.5bn. Instead, Rio Tinto agreed a tie-up with rival mining firm BHP Billiton.