Yang Hengjun -- a novelist and former Chinese diplomat -- went missing shortly after he travelled to the southern city of Guangzhou last week, friends said.

The Sydney Morning Herald reported that Yang had travelled to China with his wife and son on January 18, but never made a planned internal flight to Shanghai.

"Chinese authorities informed the Australian Embassy in Beijing that they have detained Mr Yang Hengjun," Australia's Department of Foreign Affairs and Trade said in a statement late Wednesday.

"The Department is seeking to clarify the nature of this detention and to obtain consular access to him... as a matter of priority." The Australian government is believed to be in contact with Yang's friends and family, as well as Chinese authorities.

Authorities in Guangzhou did not immediately respond to a request for comment.

Yang's disappearance prompted fears that he may be the latest victim of an increasingly broad dragnet by Chinese security services.

Australia recently expressed concern about China's detention of two Canadians in apparent retaliation for the arrest in Canada of a senior executive of Chinese telecom giant Huawei.

Tensions have also been strained between China and Australia in recent months.

Australia banned Huawei from participating in its 5G network in August over security fears. The United States and New Zealand have taken similar steps.

Yang's friend and journalist John Garnaut described him as "brilliant" and "a courageous and committed democrat".

"This will reverberate globally if authorities do not quickly find an off-ramp," he warned.

Yang had worked in the ministry of foreign affairs in Hainan province, but later left for Hong Kong in 1992 and the US in 1997 where he worked for the Atlantic Council think tank.

He later took up Australian citizenship -- although Beijing does not recognise dual nationality -- and wrote a series of spy novels and a popular Chinese-language blog.

Once described as China's "most influential political blogger", Yang went missing once before in 2011, describing his disappearance as a "misunderstanding" when he resurfaced days later.