(CNN) -- A top Australian government official met with Chinese authorities Saturday to discuss the arrest on spy charges of an Australian mining executive.
The visit by Trade Minister Simon Crean came nearly a week after Stern Hu and three of his Chinese colleagues at mining company Rio Tinto were detained on suspicion of espionage and stealing state secrets.
Crean told reporters he expressed Australian's "strong concern" over the detention of Hu, the general manager of Rio Tinto's Shanghai office, where all four employees work.
"The Australian government is deeply concerned about the position surrounding Mr. Hu," Crean said. "Obviously from a consular perspective we are concerned about his welfare, the access of the family to Mr. Hu, the ability for him to obtain speedy expedition of his case if charges are to be laid and of course legal representation."
The trade minister, who was in China on a previously scheduled trip, said Shanghai authorities promised to convey Australia's message to the national government in Beijing.
Hu and his three colleagues -- who have not been identified -- were detained Sunday. Watch more on the arrests
China's foreign ministry has said Hu "gathered and stole state secrets from China via illegal means, including bribing internal staff of Chinese steel companies" during China's iron ore negotiation with foreign miners earlier this year.
Rio Tinto has called the charges surprising and said it is not aware of any evidence to support an investigation.
Chinese officials have not told Australia what the charges involve, Crean said Saturday.
A reporter asked Crean about press reports saying Hu gave a copy of the Chinese group's internal meeting minutes to Rio Tinto.
"You're going on news reports. So are we," Crean said. "What we are seeking is greater clarity. But if those reports are right, it clearly demonstrates this is clearly a matter pertaining to commercial activity."
Australian Foreign Minister Stephen Smith earlier said the evidence, if true, may not merit the charges.
"It's difficult for a nation like Australia to see a relationship between espionage or national security and what appear to be suggestions about commercial or economic negotiations," he said.
Stealing state secrets carries severe penalties of up to life imprisonment in China, said Vivienne Bath, a professor at Sydney Law School at the University of Sydney.
The Australian consul general met with Hu on Friday, Crean said, and Australia continues to press for further consular access as well as visits by Hu's family.
Australia is also pressing China to provide Hu with legal representation, which is not guaranteed.
"In cases involving state secrets, the approval of the interrogating officers is required for you to actually have a legal representative," Bath told the Australian Broadcasting Corporation. "I think that one of the jobs of the consular official would be to push very hard for him to be properly legally represented."
Hu appeared in good health when the consul general visited him Friday, Crean said.
The arrests of Hu and his colleagues come after Rio Tinto broke away from a $19.2-billion investment deal with state-owned Chinalco last month.
The deal with Chinalco was signed in February and was awaiting a review by Australia's Foreign Investment Review Board.
The deal soured as opposition party members ratcheted disapproval, saying it would put Australian resources at strategic risk. Others saw the deal as an alliance that would further link resource-rich Australia with the commodities-hungry Chinese market.