The wife of Australian writer and political commentator Yang Hengjun, who was formally arrested on suspicion of spying in China, says "there's no way" she can connect her husband with the accusation.

Key points: Yang Hengjun has been formally arrested more than seven months after he was detained

Yang Hengjun has been formally arrested more than seven months after he was detained Foreign Minister Marise Payne says the Government is concerned and disappointed

Foreign Minister Marise Payne says the Government is concerned and disappointed If he is charged and convicted, the penalty ranges from three years in jail to the death penalty

"There's no way I can associate him and the word spying together, " Mr Yang's wife Yuan Ruijuan said.

"We've lived in the US, we've lived in China but we are just ordinary people.

"There's no way I can connect him and this accusation in the same sentence."

Mr Yang is potentially facing the death penalty or years in jail.

Ms Yuan said she has lost weight and been diagnosed with depression.

"The whole family was always worried that his political writings would bring trouble but no one ever thought they'd bring this type of charge," she said.

Dr Yang, 54, had been under investigation for harming China's national security, but Australian diplomats have now been notified that he is under suspicion of committing crimes of espionage.

ABC correspondent Bill Birtles said Dr Yang's arrest was another step towards being charged in China's opaque and secretive legal system.

He has been detained without access to family or lawyers since January. However, he has been visited by consular staff seven times in that period.

Foreign Affairs Minister Marise Payne said government efforts to gain additional information had been difficult.

"The Government is very concerned and disappointed to learn that Australian citizen and academic Dr Yang Hengjun was formally arrested in China on suspicion of espionage on 23 August and will continue to be criminally detained," she said.

"Our thoughts are with Dr Yang and his family at this very difficult time.

"Dr Yang has been held in Beijing in harsh conditions without charge for more than seven months. Since that time, China has not explained the reasons for Dr Yang's detention, nor has it allowed him access to his lawyers or family visits."

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She said consular staff had been approved for another visit to Dr Yang on Tuesday.

"We have serious concerns for Dr Yang's welfare, and about the conditions under which he is being been held. We have expressed these in clear terms to the Chinese authorities," she said.

"I respectfully reiterate my previous requests that if Dr Yang is being held for his political beliefs, he should be released."

China's Foreign Ministry Spokesperson Geng Shuang lashed out at Australia's response at a press conference on Monday.

"China deplores the Australian statement on this case. I would like to reiterate that China is a country with rule of law," he said.

"Australia should respect China's judicial sovereignty and not interfere in any way in China's lawful handling of the case."

He stressed the case was still being handled and that Dr Yang's rights were "fully guaranteed", adding that "he is in good physical condition".



One of Dr Yang's lawyers in Beijing, Shang Baojun, told the ABC charges may still be some time off.

"It's very hard to say, maybe a few months, maybe one or two years or could be even longer," he said.

The ABC has contacted the Chinese embassy in Canberra but is yet to receive a response.

Yang Hengjun has not seen his family since he was detained in Guangzhou, China, in January. ( Supplied: Twitter )

Reached by phone, Ms Yuan confirmed she had been issued the formal arrest notice in Beijing and had been told not to give it out to anyone else.

She said she and her husband had both been working as daigou, a kind of overseas personal shopper, selling products online to China.

She went on to say that the couple had no connections to any officials.

Ms Yuan said the investigation was ongoing, and her husband remained detained in Beijing.

She has been granted permanent residency by the Australian Government, but China's Government has barred her from leaving the country.

Feng Chongyi, an academic at the University of Technology Sydney and a friend of Dr Yang, said China was trying to pressure Australia over its ban on Chinese telecommunications giant Huawei taking part in the 5G mobile infrastructure rollout.

"To exercise pressure on Australia and the United States, we know Australia is regarded by Chinese authorities as the closest ally to the US in dealing with Huawei," he said.

Dr Feng called for Dr Yang's release.

"It is absolutely outrageous; they can provide no evidence for these politically motivated charges," Dr Feng told Reuters.



Yang could face death penalty if charged with espionage

Under Chinese law, the penalties for espionage charges range from three years in jail to the death penalty.

"If he's convicted of that offence that's a capital offence," Dr Yang's lawyer Rob Stary said.

"So we're worried about that [and] we're worried about his interrogation."

Dr Yang had been living with his family in New York, where he was a visiting scholar at Columbia University.

He flew to the Chinese city of Guangzhou with his wife and child in January this year.

Dr Yang's family were allowed to board their connecting flight to Shanghai, but authorities escorted him from the airport.

Later that month, the Chinese Foreign Ministry confirmed the arrest, saying Dr Yang was suspected of "engaging in criminal acts that endangered China's national security".

The Australian Government has grown increasingly critical of China's treatment of Dr Yang in recent months, with Senator Payne saying she was "deeply disappointed" he had been moved to criminal detention in July.