Jerome Cohen, an expert on protecting the rights of detainees in China, said the government may discourage public scrutiny in these cases to prevent allegations about its own shortcomings. ''Governments, as you know, fear publicity, which often brings criticism for alleged ineptitude and ineffectiveness,'' Professor Cohen said.

Fairfax Media reported on Saturday that Du Zuying, an Australian cardiac surgeon whose lawyers and family say has been stripped of a two-thirds share of a $300 million business, had spent nearly two years in jail without public knowledge.

Dr Du requested in October last year media be notified and his case made public in order to place scrutiny on Chinese officials, who had allegedly taken bribes to keep him in jail.

But Australian consular officials urged his family to be ''extremely cautious'' in approaching the media and issued media ''guidelines'' that outline risks but no benefits. On Saturday, Dr Du's son, Tommy, urged Senator Carr to raise his father's case with senior Chinese officials, after Senator Carr rejected a similar request in March. Next month, he will get an opportunity to meet with Politburo member Liu Yandong, who is planning a visit to Australia.

On Friday Australia's ambassador to Beijing, Frances Adamson, for the first time wrote to a senior Chinese official to press the doctor's case.

The number of ethnic Chinese-Australians falling foul of China's often-murky legal system is rising with economic interdependency between the two nations. Figures provided to Fairfax Media this week show 38 Australian citizens have been in Chinese jails this year on offences ranging from fraud to murder.