Beijing: China's secretive state security agency has failed to respond to an application by human rights lawyers to access Australian blogger Yang Hengjun, who is detained in Beijing.
Lawyer Shang Baojun said the application was lodged on Monday with the Beijing state security bureau and a response is usually processed within 48 hours.
Mo Shaoping, one of China's highest-profile defence lawyers, said: "We can only urge [the bureau] to reply soon, on whether it will agree for lawyers to meet him or not."
Mr Yang's family was last week issued a notice saying he was under investigation by the bureau for espionage.
Under Chinese law, the right to a lawyer is suspended for state security cases, and any meeting in these circumstances must be approved by police.
Mr Yang is being held in "residential surveillance at a designated place" - a form of isolated custody used to question suspects in national security, terrorism or serious bribery cases. The location is likely to be a hotel or guesthouse on the outskirts of Beijing.
Mr Yang was detained 12 days ago as he arrived at Guangzhou airport with his wife and step-daughter from New York, where they live.
He has received a consular visit from Australian embassy staff, but there is no right for family members to visit. His wife, who was previously a high-profile patriotic blogger in China under the name Yuan Xiaoliang, is understood to be staying in Shanghai.
Mr Yang can be held in these conditions for up to six months before any charges are laid.
Mr Yang's friends in Australia are concerned that his track record of online writing about political reform could be the reason for his detention, despite his "moderate" writing in recent years.
In recent weeks, Chinese police had been told to stay alert for "foreign infiltration".
On Tuesday, in another case, the wife of Taiwanese NGO worker Lee Ming-che, who had been held incommunicado in residential surveillance for six months in 2017, complained that she had been again barred from visiting him in prison.
Lee's arrest during a visit to mainland China, and later sentence of five years in prison for inciting others to subvert state power, deepened the rift between China and Taiwan. His court appearance in September 2017 was the first time his wife, Lee Ching-yu, saw him - six months after his arrest.
The trial was webcast live, and Lee confessed to writing and distributing online articles that criticised the communist party and promoted democracy.
Both of the lawyers working on Mr Yang's case previously worked on the late Nobel Prize laureate Liu Xiaobo's case.
They also acted for Liu's wife, Liu Xia, who was under house arrest for eight years, before being allowed to leave China last July after a diplomatic push by German Chancellor Angela Merkel.