Only one high-profile case remains but numbers rise, writes Angus Grigg.
When former prime minister Julia Gillard visited Beijing in   April 2013, she was peppered with questions about the four high-profile Australian business people languishing in Chinese prisons. 
A perception that all were victims of a corrupt court system, or had been targeted by government officials, soured what was otherwise seen as a successful visit.
At the time, it was one of the biggest bilateral issues between Canberra and Beijing. Since then it has faded, as all but one of the four have been released.
Only Stern Hu, Rio Tinto's former head of iron ore trading, remains in custody. As The Australian Financial Review reported on Friday, Hu has had his 10-year sentence for corruption and industrial espionage reduced twice since being convicted in 2010. He is expected to receive another sentence reduction next year, which would have him released in early 2018.
His eventual release will come after that of Sydney heart surgeon Du Zuying, who was freed in   July 2014. He spent more than three years in a Chinese jail after a dispute with his business partner.
The next to be released was education entrepreneur Charlotte Chou in   December 2014 after six-and-a-half years in prison.
Then, last month, Matthew Ng was freed - from the Australian prison to which he had been transferred from China - after five years in custody.
While the number of high-profile cases has fallen in recent years, the actual number of Australians imprisoned in China looks to be on the rise. According to the Department of Foreign Affairs and Trade, 42 Australians remain in Chinese jails. Of these, 20 were imprisoned for fraud-related offences and nine for drugs, the department said.