Officials have kept tight-lipped about details of the controversial legislation, which is being drafted by China’s top legislative body albeit with many Hong Kong ministers left in the dark, reports Hong Kong Free Press.

Secretary for Security John Lee on Wednesday evaded a reporter’s request to confirm reports that arrested persons may be held in special detention centres for however long authorities like, in violation of international human rights laws, the newspaper reported.

“We have to wait until the proper promulgation of the law so that we will know exactly what the law says and requires us to do,” he told reporters at the Legislative Council as quoted by the newspaper.

“The preparation work is to ensure that we will be able to discharge [the law’s] functions and responsibilities.”

Right activists have now expressed concerns over the law.

Claudia Mo, a pro-democracy lawmaker, tweeted: "On China’s #HongKong national security law Official here practically says #Beijing CAN JUST DO IT #CarrieLam sellout."

“It sounds hyperbolic, but anything goes in Hong Kong these days. Reign of terror. Orwellian Hong Kong. They will do anything to frighten Hongkongers into silence and inaction,” pro-democracy lawmaker Claudia Mo told HKFP.

The Civic Party’s Alvin Yeung also told HKFP that despite lack of “textual proof” to support the suggestion, the government’s refusal to disclose details of the law raised the possibility of such a practice: “[K]nowing that China has a track record of unreasonable and prolonged detention of dissidents, it is only logical we expect that to happen in Hong Kong after enactment.”