Rio Tinto says its workers are innocent of all charges
China has warned against politicising the trial of four Rio Tinto executives, hours after Australia expressed concern over the conduct of proceedings.
Australian national Stern Hu and three other Rio executives go on trial in Shanghai on Monday.
The men are charged with giving and receiving bribes, and illegally obtaining commercial secrets.
Australian Prime Minister Kevin Rudd said the "world will be watching" how the court case is conducted.
Part of the trial of the four executives is to be held behind closed doors.
It will be open to hear the bribery charges but then be closed to deal with allegations about the theft of commercial secrets.
"I was disappointed that there was an indication from Chinese officials and the court that Australian officials would not be present, or be able to be present, for the commercial information charge," Foreign Minister Stephen Smith told journalists.
Australia has asked China to reconsider closing that part of the trial, a foreign ministry statement said.
The Anglo-Australian mining giant, Rio Tinto, which throughout has affirmed the innocence of its four executives, has called for a "transparent and expeditious process".
The case of Stern Hu, who has been held since July 2009, has soured relations between Beijing and Canberra, reports the BBC's Nick Bryant.
China is now Australia's largest trade partner and it is also a vital customer for Rio Tinto.
As if to drive home that point, the company's chief executive, Tom Albanese, will be taking part in a Chinese government think-tank session in Beijing on global economic co-operation at the same time as his colleagues are on trial in Shanghai, our correspondent adds.