Mining giant Rio Tinto says allegations that some of its employees in China have been engaged in bribery are "wholly without foundation''.
Chinese authorities claim four employees of the world's third-biggest miner bribed Chinese steel mills officials during annual iron ore contract price negotiations.
Rio Tinto iron ore chief Sam Walsh today bluntly rejected the allegations and said the group was continuing to operate in China.
"Rio Tinto believes that the allegations in recent media reports that employees were involved in bribery of officials at Chinese steel mills are wholly without foundation,'' he said in a statement.
"We remain fully supportive of our detained employees, and believe that they acted at all times with integrity and in accordance with Rio Tinto's strict and publicly stated code of ethical behaviour.
"Rio Tinto remains very concerned about the four employees detained in Shanghai.''
The company said the federal is keeping it fully briefed on efforts to assist the employees, which include Australian citizen Stern Hu.
"Rio Tinto continues to operate in China and is maintaining high levels of iron ore shipments from Australia,'' Mr Walsh said.
China's official China Daily newspaper recently claimed the Rio Tinto employees had bribed executives from all 16 of the country's major steel mills.
The report said they targeted key officials from firms which negotiate iron ore prices with large foreign suppliers.
Rio Tinto, the world's second-largest iron ore producer, has been taking the lead role in negotiations to determine a new contract price for iron ore.
The stakes are high because once agreed, the contract price typically is adopted by the world's other large iron ore producers.
The dealings have been more protracted than ever before, with Chinese negotiators demanding a better deal than other major Asian and European customers have accepted.
For the first time in the decades-old benchmark pricing system, negotiations have continued past a June 30 deadline, and Chinese steel works have been paying a higher for iron ore than their competitors.
In recent days reports have also suggested Rio Tinto is readying to evacuate other employees from China.
Rio Tinto spokeswoman on Friday refused to comment on those reports.
Mr Hu's detention has sparked claims Prime Minister Kevin Rudd is failing to do enough to help the Australian man because of China's economic might.