Four employees of mining giant Rio Tinto - Australian national Stern Hu and three Chinese employees-  all accused of taking bribes and violating commercial secrets, stood trial in China on Monday.

Though Canberra has called for transparency in the three-day trial, hearings on the industrial espionage charges will be closed.

Foreign reporters were excluded from the trial and only a few reporters, who appeared to be from state-run domestic media, were allowed in the Shanghai No 1 Intermediate People’s Court early Monday.

The four defendants were arrested last July during contentious iron ore contract negotiations which later collapsed, and after Rio snubbed a near 20-billion-dollar cash injection from state-run Chinese mining firm Chinalco. Chinese media last summer accused the four of seeking information about Chinese mines and steel mills, which many firms – included Rio who claims its employees did nothing wrong - consider legitimate market information.

China has excluded Australian diplomats from observing the part of the trial concerning commercial secrets, drawing protest from Canberra, which says they have the right to be present for the whole trial.

A Chinese researcher in a think-tank run by the nation’s Ministry of Commerce said there was a strong case against the Rio employees and warned Australia to keep a distance.

The trial, which has highlighted the risks of doing business in a country with a huge market but close ties between the ruling Communist Party, police and courts, is being widely seen as a test of whether China is willing to honour commitments to foreign investors and be a responsible member of the world community.

Australia has said consular officials will attend trial sessions on the bribe-taking charges and it had asked China to reconsider the closure of the trade secrets hearings.

Beijing has insisted the case will be handled by the book and it will “fully guarantee” the rights of the defendants, who include Chinese nationals Wang Yong, Ge Minqiang and Liu Caikui.

Defense lawyers interviewed on Friday did not yet know in which order the charges would be considered, or which days would be open. The verdict may not be immediately announced.