BEIJING - CHINA said on Tuesday it was handling the case of a detained Australian mining executive according to law, as it sought to allay foreign concerns about doing business in the world's third biggest economy.

'This is an independent judicial case,' foreign ministry spokesman Qin Gang said when asked about Rio Tinto executive Stern Hu, who was detained on July 5 in Shanghai amid allegations of industrial espionage.

'Competent authorities, in line with the facts, have taken relevant measures in accordance with the law to detain this staff member of Rio Tinto.'

China's state-run media reported Tuesday that five big steel firms were also being investigated in connection with the arrest of Australian passport-holder Hu and three Chinese colleagues.

The Australian government has complained that China has not given them enough information about Hu's case.

And analysts said Hu's arrest had sent tremors through the international business community about the potential risks of doing business with China.

But Qin said Hu's case should have no bearing on how foreigners perceived doing business in China.

'China's policy of mutual benefit and win-win trade will not change,' he said.

'Over the past 17 years, China has attracted more international investment than any other developing nation largely due to such policies... we will continue to offer favorable conditions.' -- AFP