The Australian government is of novelist and influential online commentator Yang Hengjun, who did not complete the second leg of a journey from New York to Shanghai after flying out of Australia on January 18 with his wife and son.
Australia's foreign affairs department on Wednesday said it was "seeking information about an Australian citizen who has been reported missing in China".
Dr Yang's PhD supervisor, Associate Professor at the University of Technology Sydney, Dr Feng Chongyi told SBS Mandarin he believed that his colleague "must have been detained by the Ministry of State Security" at Guangzhou airport.
Dr Feng, who said he's been in contact with Dr Yang's family, speculates that the main purpose of such an action would be to "apply pressure" on the Australian government following Beijing's
"Australian government made an announcement on the detention of a few Canadian citizens, demanding their release. In my opinion, Yang's disappearance is related to that," Dr Feng said.
"China wants to expand the scope of this. They pose pressure on the Australian and Canadian governments by holding citizens."
Former China correspondent John Garnaut says Dr Yang is "not only brilliant but extraordinarily popular among the Chinese-speaking world and a courageous and committed democrat".
"This will reverberate globally if authorities do not quickly find an off-ramp," Mr Garnaut wrote on Twitter on Wednesday.
Similar concerns were raised for Dr Yang's safety in 2011 when he disappeared after calling a friend from a Chinese airport claiming he was being followed by three men.
He later claimed the matter had been a "misunderstanding".
In an interview with SBS Mandarin following the 2011 episode, Dr Yang said: "I'm sorry for my negligence. I was ill, and my phone was turned off. I didn't keep in touch with my family, and this caused concerns to my family, friends and a lot of other people. I feel very sorry for that."
Dr Feng said Dr Yang's disappearance signalled a "significant move".
"[They are] holding him in Guangzhou and then taking him directly back to Bejing. It was from the ministry, the MSA. It's not a small move from a local, minor government."
