National legislators will review a draft decision on establishing and improving a legal system for the Hong Kong Special Administrative Region that would safeguard national security, Zhang Yesui, spokesman for the 13th National People's Congress, said at a news conference in Beijing on Thursday.

The draft decision is to be presented as a motion and discussed during the annual session of the NPC, the top legislative body. More details on the decision will be given when the session commences on Friday.

Zhang said the NPC is exercising the power authorized in the Constitution to establish and improve a legal framework and enforcement mechanisms for the SAR to safeguard national security in light of "the new circumstances and needs".

The draft follows months of unrest in Hong Kong that started in June, triggered by a bill to amend the SAR's extradition law.

The unrest has transformed into wider violence against the police and local government, with rioters attacking passersby, smearing the national flag and emblem and vandalizing buildings.

The chaos continued after the bill was officially withdrawn in October, and the Hong Kong Legislative Council has failed to enact a national security law, which has been shelved since 2003.

"National security is the bedrock underpinning the stability of the country and serves the fundamental interests of all Chinese people, including Hong Kong compatriots," Zhang said.

Hong Kong is an inseparable part of China. The fourth plenary session of the 19th Communist Party of China Central Committee clearly required a legal framework and enforcement mechanisms to be established for safeguarding national security in Hong Kong, he said.

As the NPC is the highest organ of State power, it is "absolutely necessary" that it establishes and improves, at State level, Hong Kong's legal system and enforcement mechanisms to safeguard national security and solidify the "one country, two systems" principle, he said.