China has no power to introduce a national security law for Hong Kong as such power is vested exclusively with the local legislature, according to veteran lawyer Martin Lee.

The lifelong democracy advocate and founder of the Democracy Party, said China's proposed legislation of the controversial law, and its enforcement in the territory, would breach an international treaty under which a 50-year high degree of autonomy was promised to the former British colony restored to China in 1997.

Lawyer Martin Lee Chu-ming, nicknamed the father of democracy in Hong Kong, gives an interview in the city on May 22, 2020. (Kyodo)

"Within the 50 years of the effective period of the Basic Law, China's Constitution does not apply in Hong Kong," Lee told Kyodo News. "Thus the National People's Congress has no power to legislate for Hong Kong under the Basic Law. Such power is vested with the local legislature."

Citing disrespect to China's sovereignty and signs of foreign interference in Hong Kong affairs, the highest legislative body will deliberate on a draft decision to legislate a national security law and enforcement mechanism for Hong Kong this week.

Although the Basic Law, the mini-constitution in effect since the handover, stipulates that Hong Kong has to enact an anti-subversive law on its own, a bid by the government in 2003 failed as 500,000 protesters took to the streets. The legislative process has been suspended ever since.

The national security law would ban separation, subversion, foreign interference and terrorism in Hong Kong affairs. A central agency would be set up and operated in Hong Kong.

The law would be annexed in the Basic Law and promulgated by the Hong Kong government. But, Lee said only national law could be annexed, and the law in question is not a national law.

"This national security law is only applicable in Hong Kong, specifically introduced to Hong Kong and not applicable in all of China. So, this is not a national law, as mentioned in Article 18," Lee said.

He added that the local legislature could enact such a law, but Beijing wants to create a precedent. With the NPC Standing Committee legislating for Hong Kong, circumventing the Legislative Council, it can move quickly in the event the pro-democracy camp wins a majority of seats in September's election, and it loses control over the local legislature.

Against a backdrop of growing anti-China sentiment manifested during months-long demonstrations last year, the pro-democracy camp scooped up most of the seats in the district council elections in November, loosening the grip traditionally held by the pro-establishment camp. Many have expected the trend to spread to the legislative election.

"Everyone should abide by the laws, the Constitution, the national laws and the Basic Law as well. But when those in power break their own laws, what can we do? We can only point it out. Let international communities understand that signing deals with China could be useless," as China might cherry-pick what is in its favor and shift the blame when things go wrong, Lee said.

"China is getting impatient. It is moving away from what was declared in the (Sino-British) Joint Declaration about Hong Kong people ruling Hong Kong and high degree of autonomy. They are ignoring the Basic Law. They treat international treaties, the joint declaration and Basic Law all the same -- use it when in their favor and ignore it when not," Lee said.

The draft decision was expected to be passed by Thursday when the NPC session ends, and the details of the law could be hammered out by the NPC Standing Committee when it meets in June, at the earliest. However, pro-Beijing politicians and the Hong Kong government voiced their wholehearted support of the legislation soon after it was announced.

Justice Secretary Teresa Cheng has said in her blog, no doubt, the parliament has the power to make decisions relating to Hong Kong and to ensure the Constitution is implemented.

"There are doubts as to whether the NPCSC can legislate national security laws for the HKSAR (Hong Kong Special Administrative Region). Such doubt is totally unwarranted," she said.

Cheng said while Hong Kong is authorized to legislate national security laws, it "does not preclude the central authorities from legislating at a national level for national security. To blindly vilify laws relating to national security is totally irrational...as the HKSAR cannot do it, it is not surprising that the NPC takes action at the national level."