CANBERRA, Australia (AP) — Australia’s foreign minister on Monday described as “unacceptable” the daily interrogation of a shackled Chinese Australian writer detained in Beijing on suspicion of espionage since January.

Yang Hengjun was taken into custody upon arriving in southern China's Guangzhou from New York in January with his wife, Yuan Xiaoliang, and his 14-year-old stepdaughter.

Foreign Minister Marise Payne said she was “very concerned” by reports from Australian officials following their latest monthly consular visit to Yang, who remains in criminal detention. Her office did not immediately say when that visit had taken place.

“His circumstances of detention include increased isolation from the outside world, with restrictions on his communications with family and friends and the resumption of daily interrogation, including while shackled,” Payne said in a statement. “This is unacceptable.”

Australia had made repeated requests to Chinese authorities for an explanation of the charges against the 54-year-old spy novelist, Payne said.

“We have also made repeated requests for him to be afforded basic standards of justice, procedural fairness and humane treatment, in line with international norms, including access to his lawyers and to his family, both of which continue to be denied to him,” Payne said. “This has not led to any substantive changes in his treatment.”

“We will continue to express our expectations in clear terms to the Chinese authorities — both in Beijing and in Canberra — including that Dr. Yang be released and that, while his detention continues, he be treated fairly and humanely,” she added.

The Chinese Embassy in Australia did not immediately respond to a request for comment.

Some analysts suspect Yang has been detained because of Chinese anger over Australian legislation passed by Parliament last year that outlaws covert foreign interference in Australian politics and institutions.

Prime Minister Scott Morrison on Monday announced an 88 million Australian dollar ($60 million) investment in a new Counter Foreign Interference Taskforce to disrupt and deter anyone attempting to undermine Australia’s national interests.

Morrison said he shared Payne’s concern for Yang.

“We would like to see the issues about access to lawyers, about getting a clear enunciation of what the matter is that have been brought against the Australian citizen at the center of this case, and ... that his access to family and treatment that would meet, you know, world standards is being provided to him,” Morrison told reporters.

“The most recent consular access was a matter of great concern to me and the foreign minister and we will continue to make those representations on behalf of an Australian citizen,” he added.