"I reiterate my call for the immediate and unconditional release of all people arbitrarily arrested and detained under these laws," Volker Türk said in a statement.
"My services and other human rights experts at the United Nations have expressed their concerns on several occasions that this legislation does not respect China's obligations under international human rights law," Türk said.
"As the UN Human Rights Committee has already stated, this legislation must be abolished and, in the meantime, it must not be applied," he added.
Türk also recalled the seven people convicted under a new law approved last March that considerably expands the scope of crimes such as treason, insurrection, state secrets, sabotage, risks to national security and external interference.
"I have already expressed my concerns that these broad and vague provisions can be applied arbitrarily to restrict freedom of expression and target dissenting voices, civil society activists and human rights defenders," Türk said.
Today, Hong Kong accused Western countries of several political attempts to influence the verdict of the trial that declared 14 opponents guilty of subversion for violating the national security law imposed by Beijing.
A government spokesperson firmly condemned these "inappropriate statements" from the media, anti-Beijing politicians or interest groups, and from Western countries, in particular the United States, the United Kingdom and Australia.
His "thoughtless comments were inappropriate and ignore the spirit of the rule of law," he declared.
