The family of an Australian writer Yang Hengjun, detained for more than four years in China on suspicion of spying, has penned a letter to Prime Minister Anthony Albanese, pleading for him to do “all in his power” to secure their father’s release ahead of a high-level visit to Beijing.

The letter, sent to the prime minister last week and released publicly Tuesday, refers to the recent release of Cheng Lei and pleads for “a second miracle”.

“We have been inspired by the wonderful news of Cheng Lei’s release and return to Melbourne,” Dr Hengjun’s family wrote.

“We hope that you, Foreign Minister Penny Wong and Ambassador Graham Fletcher can achieve a second miracle by saving our father.”

Mr Albanese will hold talks with China’s President Xi Jinping and Premier Li Qiang during a four-day visit to Beijing and Shanghai next week.

The visit will make Mr Albanese the first Australian leader to visit the nation in seven years.

‘Situation critical’: Family says there is a small window of opportunity to act

The 57-year-old democracy advocate, who previously worked for China’s Ministry of State Security, was intercepted at Guangzhou airport in 2019 and accused of spying.

He was formally detained in July of that year and in August 2019 arrested on suspicion of committing espionage crimes, a charge he has always denied.

Dr Yang’s children have shared excerpts of a consular report which noted a rapid decline in his health.

“He had trouble standing and had collapsed several times … I’m sick, I’m dying,” the report read.

In August, the Chinese-born Australian citizen was told he had 10-centimetre cyst on his kidney but his children say he was provided no further detail.

“We request that you do all in your power to save our father’s life and return him immediately to family and freedom in Australia,” they wrote.

“We ask you to act now, in this narrow window of opportunity prior to your departure.

Advocate and close friend of Dr Yang, Chong Fengyi, says Australia has an obligation to hold China accountable.

“It’s morally indefensible position to fully normalise relations with China when the CCP [Chinese Communist Party] has kept Yang Hengjun as a hostage,” he said.

“It only depends on the political will and political consideration of Chinese authorities.”

Professor Fengyi says while he is hopeful the release of Cheng Lei may signal a shift from the Chinese authorities, Dr Yang’s case is far more complicated.

“The bad news is that Yang Hengjun’s situation is much more serious than Cheng Lei, and he was detained almost two years longer than Cheng Lei,” Professor Fengyi said.

“If they released Cheng Lei on humanitarian grounds, they should release Yang Hengjun or at least do the same to Yang Hengjun.”

Mr Albanese said he would raise concerns about Australians detained in China when he met with Mr Xi next week.

“We have raised concerns including at meetings I have had in the past with President Xi,” Mr Albanese said.

“We are very pleased that Cheng Lei has been able to be rejoined with her daughters and family in Melbourne. That was a good outcome.

“We always raise cases of Australian citizens, each case is different, but each case is important.”

Professor Fengyi says it may be the last chance for diplomacy to bring Dr Yang home.

“The visit of the prime minister to China, if it’s not the last chance it is a very rare opportunity to get Yang Hengjun back to Australia,” he said.

Dr Yang’s first letter from his cell

Dr Yang’s family last month received their first letter from their father since he was arrested and detained almost five years ago.