John Garnaut was commissioned in 2016 by then-Prime Minister Malcolm Turnbull to write a classified report on Chinese influence on Australian politics, leading to sweeping laws in 2018 banning covert foreign political interference and a diplomatic rift between Australia and China, its biggest trading partner.
Garnaut told Australian Broadcasting Corp. in an interview broadcast on Monday that he advised spy novelist and friend Yang Hengjun not to travel to China after Yang revealed he had been questioned by a Chinese government official in Sydney in 2018 about Garnaut's investigation.
"He was asked about me, what was the nature of our relationship, what was I doing. What was I working on," Garnaut said.
Yang, a 53-year-old visiting scholar at Columbia University in New York and a former Chinese diplomat, did not take Garnaut's advice and flew to China with his wife, Xiaoliang Yuan, and his 14-year-old stepdaughter.
Yuan said she had not seen her husband since they were separated by Chinese officials when they landed at Guangzhou Airport on Jan. 19.
Foreign ministry spokeswoman Hua Chunying said in January that Yang was "suspected of engaging in criminal activities endangering China's national security." He is being held in Beijing, where the Australian Embassy has been allowed consular access to him. ABC reported that Yang had yet to be formally charged.
The Australian government has urged China to treat Yang transparently and fairly.
Yuan is living in Shanghai. She said she is not allowed to leave China and her husband has not seen a lawyer.
"I have absolutely no idea whether he is well or even if he is alive or not," she said through an interpreter.
"It gets harder as time passes, mainly because I can't see him. I would have felt better if the lawyers could see him and verify that he is all right," she added.
A friend of Yang, University of Technology Sydney academic Feng Chongyi, was detained for two weeks in 2017 while visiting China to research human rights lawyers.
Feng told ABC that he had been questioned for an entire day in detention about Garnaut's investigation. Feng said his interrogators had known Garnaut was working for the prime minister.
"They knew a lot about him. During the interrogation, they did not hide that they were angry with him," Feng said.
Chinese Foreign Ministry spokesman Lu Kang said he had not seen the ABC report. But Lu said the Chinese government had always opposed any interference in the internal affairs of other countries.
"As for activities carried out by Chinese embassies and consulates in other countries, these activities aim at promoting mutual understanding between China and the regions or countries where the diplomatic mission are based, and enhancing mutual understanding and friendship among the people, including serving as the bridge of cooperation between the business community of each other," Lu said.
"I did not see any difference between the activities carried out by Chinese embassies and consulates in other countries and those conducted by foreign diplomatic missions in China," he added.
Associated Press writer Christopher Bodeen in Beijing contributed to this report.