Two lawyers hired by the wife of an Australian detained in Beijing for suspected espionage have said they were denied access to him by Chinese authorities, who said the detainee had not agreed to their appointment.

Yang Hengjun, a 53-year-old Chinese-born writer, was detained in the southern city of Guangzhou while waiting for a transfer to Shanghai in January. He had flown in from New York.

Yang was taken to Beijing where China has said the city’s State Security Bureau is holding him under “coercive measures”, a euphemism for detention, while he is investigated on suspicion of “endangering state security”.

One of the lawyers, Mo Shaoping, said the state security bureau informed him on Friday that Yang did not accept lawyers appointed by his family. Mo said the bureau rejected his request to verify this with Yang in person.

The other lawyer, Shang Baojun, told Reuters: “The thing we’re most concerned about is whether this is the real wish of Yang Hengjun.”

They hoped to glean more information when Australian consular officials are next allowed to meet Yang, Shang said.

China’s ministry of state security said in a faxed response that questions should be referred to the agencies in charge of the case. It had previously said Yang’s rights and interests were being protected in accordance with the law.

The ministry has no publicly available contact details.

Mo previously told Reuters his client was suspected of espionage and was being held under “residential surveillance at a designated location”.

The special detention measure allows authorities to interrogate suspects for six months without necessarily granting access to legal representation. Rights groups say the lack of oversight raises concern about abuse by interrogators.