The National People’s Congress backed the bill as it wrapped up an annual session.  "It will uphold and improve the 'one country, two systems' policy," NPC chairman Li Zhanshu told delegates during the closing ceremony.

"It is in line with the constitution and Hong Kong's Basic Law and is in the interest of all Chinese people including Hong Kong people," he added.

The bill - referred to as the Draft Decision - will now pass to the Standing Committee of the Communist Party who will draw up the full details of the new law.

The bill also says that "when needed, relevant national security organs of the Central People's Government will set up agencies in Hong Kong to fulfill relevant duties to safeguard national security in accordance with the law".