Five years since his arrest, two and a half years since his trial and six months since a cyst was found on his kidney, Australian writer Yang Hengjun remains in Chinese prison without a verdict.
Though Australia's relationship with China has thawed in recent months, Beijing's detention of Australian citizens remains a sticking point.
University of Technology associate professor and Dr Yang's friend Feng Chongyi said the government should use its economic and geopolitical leverage in China to do more.
"I think they should be very clear and determined and demand for the immediate release of Yang Hengjun," he told ABC radio on Friday.
"It is an outrageous, fabricated case against Dr Yang."
In August, Dr Yang expressed concerns he could die in Chinese prison without proper medical attention after developing a large, 10-centimetre cyst on his kidney.
According to Dr Feng things have not improved.
"The torture, the detention and the harsh conditions for five years have taken a very heavy toll on Dr Yang's health," he said.
"Five years ago, he was a very healthy middle aged man.
"Now he suffers from a lot of diseases, including high blood pressure, heart disease, and especially kidney disease."
Noting the fifth anniversary of Dr Yang's arrest, Foreign Affairs Minister Penny Wong said the government was "deeply troubled" by ongoing delays in his case.
"I want to acknowledge the strength that Dr Yang has demonstrated, and the strength of his family and friends," she said in a statement on Friday.
"Our thoughts are with them all."
The government will continue to advocate for his wellbeing and interests and provide consular assistance, Senator Wong said.
Opposition foreign affairs spokesman Simon Birmingham said the coalition would support the government in using all available diplomatic means to end Dr Yang's detention.
"The unjust detention of Dr Yang is distressing, especially for his loved ones," he said in a statement.
"It is completely unacceptable that delays in Dr Yang's case continue, with no transparency over his charges, sentencing or potential release."
Dr Yang was detained in 2019 over espionage charges.
The case against him has never been publicly disclosed and his trial was held in secret in May 2021.
But his verdict has been plagued by continuous delays, having been postponed more than eight times since the conclusion of his trial.
Dr Yang has denied working as a spy.
His supporters held hopes for his release after Australian journalist Cheng Lei was freed from Chinese prison in late 2023 following three years of detention.
But at a rare press conference on Wednesday, Chinese ambassador to Australia Xiao Qian said Dr Yang's health problems had been overblown and that his case was different to Ms Cheng's.
