Yang, who’s also a blogger and an online journalist, was detained by Chinese authorities in January this year in the southern city of Guangzhou. He was on his way to Shanghai, after flying in from New York.
He was once a former Chinese diplomat but is now a dissident.
Amid escalating tensions between Canberra and its largest trading partner Beijing, China has formally arrested Yang Hengjun, the Chinese-Australian writer, after seven months of detention.
Yang has been arrested over charges of espionage. If proven, the academic may face either the death penalty or long years in jail.
Marise Payne, the Australian Foreign Minister said Australia was "very concerned and disappointed" to learn of the arrest.
Yang, who is also a blogger and an online journalist, was detained by Chinese authorities in January this year in the southern city of Guangzhou. He was on his way to Shanghai, after flying in from New York.
The Australian foreign ministry says he has been held in Beijing under "harsh conditions" since then and that they are concerned about his welfare and the conditions under which he is being held.
#BREAKING Foreign Minister Marise Payne says she's "very concerned and disappointed" about the charging of Yang Hengjun, and says the government will continue to advocate on his behalf @abcnews #auspol pic.twitter.com/WwzSfN0Vhb— Matthew Doran (@MattDoran91) August 27, 2019
Chinese Foreign Ministry Spokesman Geng Shuang has confirmed Yang's formal arrest and told Australia to back off.
"China is strongly dissatisfied with Australia's statement on this case. I would like to stress that China is a country with rule of law, and Australia should earnestly respect China's judicial sovereignty, and not interfere in China's handling of the case in accordance with the law in any way," he said.
The case is being further processed and Yang is in good health with his rights fully guaranteed, Geng added.
Who is Yang Hengjun?
An independent scholar, novelist, and blogger, Hengjun, 53, was once on the payroll China’s ministry of foreign affairs and later went on to develop a strong interest in literature and writing.
He also worked in the private sector in Hong Kong and later joined the Atlantic Council in Washington DC, as a senior fellow before finally moving to Australia.
For more than a decade he has been calling for the democratic reforms in China and maintained a popular blog on China’s international relations and current affairs.
Also known for his spy novels, under the pen name of Wei Shi, he published a trilogy of books, Fatal Weakness, Fatal Weapon and Fatal Assassination, both in print and online - books that China banned.
With more than 130,000 followers on his social media accounts, in the early 2000s his political satire and criticism of the Chinese government earned him the nickname of ‘democracy peddler’. Although in his recent writings he mostly avoided Chinese politics.
"China has been looking to clamp down on democracy efforts. This is a clear message against those efforts," said Alex Joske, an analyst at the International Cyber Policy Centre, a think-tank.
This is not the first time Yang has been arrested. He briefly went missing in 2011 from a Chinese airport. Later on, when he re-emerged, he said the matter had been a “misunderstanding”.
But a letter that he handed over to his close friend and was made public in January this year mentions that his 2011 disappearance was not a "misunderstanding" - he had been arrested.
Access to family and lawyers denied
Since his detention, Yang has been denied access to family and lawyers. His wife, Yuan Xiaoliang who is also an Australian permanent resident and one of his staunchest supporters, has been barred from leaving China.
However, Australian embassy officials have visited Yang seven times since January and were scheduled to meet him again on Tuesday, the government said.
Robert Stary, Yang's Australian lawyer, said Yang faced one charge of espionage, which he intends to deny, but the basis of the charge was unknown.
"We don't know for instance, whether it's as a consequence of his writings as a democracy activist, or a blogger or an academic," Stary told Reuters.
"He'd spent long periods in the US. So we don't know whether it's suggested he's spying for Australia, or the US or Taiwan or whoever it might be, if that's the allegation."
Various human rights activists are urging Canberra to press for Yang's immediate release.
In a statement, Human Rights Watch's Australia Director Elaine Pearson, said: "We have serious concerns about China's opaque criminal justice system where suspects face appalling treatment."
Jittery Beijing- Canberra relations
Yang’s arrest comes at what has been described as a "sensitive year" for China, which has been facing severe protests in Hong Kong over the extradition bill.
Relations between Beijing and Canberra have also been strained.
In July, a programme on ABC’s Four Corners, highlighting the plight of Uighurs in Xinjiang and their lives in labour camps caused outrage globally.
Australia stepped up its consular efforts to coax China to allow Uighur families in Xinjiang to leave and reunite with their Australian families.
China’s official media accused critics of “recklessly attacking” China. A statement released by the Chinese Embassy in Australia dismissed the programme as being "full of lies, distortion and bias".
Several Australians have faced jail time in China over the past decade, including the former head of global mining company Rio Tinto's China iron ore business, Australian citizen Stern Hu, who served eight years after a conviction in 2010 for corruption and stealing commercial secrets.
His arrest in 2008 came after tension flared between the world's top user of iron ore and its biggest supplier, Australia.
More recently, 16 staff from Australia's Crown Resorts, including three Australians, were jailed for between nine and 10 months in 2017 and fined $1.2 million for promoting gambling to lure Chinese high-rollers to its casinos.
Their jail time included the several months they were detained ahead of what was a swift trial, part of a wider crackdown on gambling in China.