China has warned Australia not to interfere in the case of a dual citizen charged with espionage in Beijing.
Chinese-Australian writer and academic Yang Hengjun could face the death penalty if the spying charges against him stand.
The Chinese foreign ministry has urged Australia to respect its sovereignty.
“China is a country with rule of law and Australia should earnestly respect China’s judicial sovereignty and stop interfering in China’s case-handling in any form,” its spokesperson Geng Shuang said.
Beijing has a long history of arresting dissidents, including dual nationals.
Experts are now urging Australia to update its travel advice for China.
Yang’s Melbourne-based lawyer Rob Stary said the allegations against him were baseless.
“We think it relates to espionage on behalf of Australia, but it’s not specified on the charge sheet,” Stary told AAP.
“We'd obviously be disturbed by that, if it was the allegation, because there is absolutely no foundation for it at all.”
Yang is a former Chinese diplomat who went on to become a pro-democracy campaigner and was made an Australian citizen in 2002.
The 54-year-old was detained in Guangzhou in January after flying into the country from New York.
He has been detained in Beijing ever since.
Australia’s foreign minister holds serious concerns for his welfare.
Embassy officials were due to visit Yang in detention on Tuesday.
Marise Payne has reminded China it must comply with international laws banning torture, inhumane treatment and arbitrary detention.
“China has not explained the reasons for Yang’s detention, nor has it allowed him access to his lawyers or family visits,” Senator Payne said.
“It is important, and we expect, that basic standards of justice and procedural fairness are met.
“I respectfully reiterate my previous requests that if Yang is being held for his political beliefs, he should be released.”
The Law Council of Australia stands ready to provide any assistance required.
“In China, espionage is punishable by death,” president Arthur Moses told AAP.
“The law council decries capital punishment and, as previously seen in other cases involving Australians facing the death penalty in other parts of the world, there is a dire need for early government intervention.”
Yang, who was a visiting scholar at Columbia University and living with his family in New York prior to his arrest, faces between three years in prison and the death penalty if found guilty of espionage.
He also has a doctorate from the University of Technology in Sydney.
