One of the Causeway Bay booksellers, Lam Wing-kee, says he does not know what the Chief Executive, CY Leung, will achieve by following-up on his case with the central government.
Lam had earlier alleged that he was kidnapped by mainland security agents when he went to Shenzhen eight months ago. He said he was then kept in a dingy room in Ningbo for weeks without access to any legal assistance.
Lam also said he had been sending banned books about mainland leaders from Hong Kong to the mainland. He returned to city last week.
During an RTHK radio programme on Tuesday, Lam said he would speak to the Hong Kong police about his case at a later date.
He was speaking before Leung confirmed that he had already sent a letter to the central government on the matter, after being accused by some pan-democratic lawmakers for not pushing Beijing strongly enough over the issue, and being unwilling to defend Hong Kong people.
Leung said the letter expressed Hong Kong people's concerns about the incident. It also questioned whether any "cross-border law enforcement" had taken place and whether the so-called 'notification system' was adequate in protecting the rights of the city's residents on the mainland
The notification system requires mainland authorities to notify the Hong Kong government whenever a resident from the city is detained on the mainland.
When asked about Leung's remarks, a foreign ministry spokeswoman said in Beijing that the central government will stick to the handover arrangement.
"I would just like to reiterate the Chinese government's firm determination to uphold the One Country, Two Systems [principle] is steadfast. The people of Hong Kong enjoy their full rights and freedoms in accordance with the law," Hua Chunying told reporters during a regular briefing.
Last updated: 2016-06-21 HKT 19:10