SYDNEY — Australia is "deeply disappointed" that Chinese-Australian writer Yang Hengjun has been transferred to criminal detention in China, Foreign Minister Marise Payne said in a strongly worded statement on Friday (July 19).

Yang, who was born in China, was detained in the southern city of Guangzhou in January amid growing tension between Australia and its largest trading partner after Chinese telecoms giant Huawei was blocked from participating in a 5G mobile project last year.

The reason for Yang's detention is not clear, but China's foreign ministry said "compulsory measures" had been taken as part of an investigation, reiterating that Yang was suspected of criminal activity endangering state security.

Ms Payne said earlier that Australia was informed on Friday that Yang had been transferred to criminal detention.

"The Australian government is deeply disappointed," she said. "The government has expressed concern about Dr Yang's welfare and the conditions under which he is held."

"We have asked for clarification regarding the reasons for Dr Yang’s detention. If he is being detained for his political views, then he should be released."

Yang, 53, whose legal name is Yang Jun, was detained in China while waiting for a transfer to Shanghai this month, after flying in from New York.

China's foreign ministry spokesman rejected Ms Payne's statement as irresponsible.

"China expresses strong dissatisfaction toward the statement made by Australia's foreign minister, urges Australia to not interfere in China's legal handling of the case in any way and cease making irresponsible remarks," the spokesman, Geng Shuang, told a briefing in Beijing.

Although Yang's recent writing has mostly avoided Chinese politics, he became prominent in the early 2000s when he earned the nickname "democracy peddler".

Ms Payne said that Australia had for months pressed China in seeking resolution of his case, and that she had written twice to Foreign Minister Wang Yi to request Yang be granted access to his lawyers.

"This has not occurred," Payne said.

"We expect basic standards of justice and procedural fairness to be met ... we will continue to press Chinese authorities for fair and humane treatment, in accordance with international norms," she said. 

Foreign Ministry spokesman Lu Kang told a news briefing in Beijing on Thursday that as far as he was aware, the case was still being investigated. REUTERS