The national security law for the Hong Kong Special Administrative Region (HKSAR) marks a milestone in advancing "One Country, Two Systems," said Zhang Xiaoming, deputy director of the Hong Kong and Macao Affairs Office of the State Council, on Wednesday.

Zhang made the remarks at a press conference held by the State Council Information Office to introduce national security legislation for the HKSAR.

The law will serve as a guardian of prosperity and stability in Hong Kong, Zhang added.

Shen Chunyao, vice chairman of the National People's Congress (NPC) Constitution and Law Committee, said the legislation will plug loopholes in Hong Kong's legal system.

"The law can effectively protect national security, prevent and punish crimes that endanger national security in relation to the Hong Kong Special Administrative Region," said Shen. "It effectively stops the loopholes in the HKSAR in relation to establishing a framework to protect national security."

Enforcement of the law is of far-reaching significance to upholding and improving the "One Country, Two Systems" policy, Shen underlined, and it is also important for national sovereignty and security, as well as Hong Kong's long-term stability and prosperity.

The press conference this morning also illustrated the significance, the purpose and the far-reaching impact of the national security law for the HKSAR.

Officials said the law is an important step to take corrective action to the unrest in the HKSAR, dismissing allegations from certain countries interfering in China's internal affairs.

The law is a landmark for upholding and improving the institutional framework of the "One Country, Two Systems" under new circumstances. It will effectively safeguard national security, lasting peace, stability and prosperity in Hong Kong, and ensure the steady and sustained development of the cause of the "One Country, Two Systems" in Hong Kong.

Chinese lawmakers on Tuesday voted unanimously to adopt the national security legislation for the HKSAR, a "resolute" effort taken by the central government that will make secession, subversion and collusion with foreign forces illegal.

The decision was made at a session meeting of China's top legislature, with emphasis on improving the legal system and enforcement mechanisms for the HKSAR while maintaining its high degree of autonomy under the principle of "One Country, Two Systems."