Former Hong Kong police commissioner Andy Tsang Wai-hung said that a special squad made up of the national-level and local-level security agencies under the city's police force to address national security matters would not be something new for Hong Kong.

Such arrangements between national-level and local law enforcement are in place in many other parts of the world, Tsang said.

Tsang was responding to the idea of setting up a designated branch of the Hong Kong Police Force to deal with national security issues once the national security law for Hong Kong is enacted.

He said that such an arrangement existed in the city during British colonial rule. "In the Special Branch, we had agencies (from the United Kingdom) responsible for safeguarding national security, working together with Hong Kong police," said Tsang, who joined the Hong Kong Police Force in the late 1970s.

The Special Branch was established in the Criminal Investigation Department of the Hong Kong police in the 1930s, and was responsible for matters of national security and intelligence.

"It's not exactly something new for Hong Kong," Tsang said. The country's top legislature, the National People's Congress, passed a draft decision on May 28 to enact a national security law for the Hong Kong Special Administrative Region to plug the legal loophole in the city.

The city hasn't completed its obligation under the Basic Law to enact its own national security legislation since its return to China in 1997. The law is being drafted by the Standing Committee of the NPC.

Many in the city have expressed opinions and offered advice on the proposed law, including how it should be implemented. The law enforcement mechanism should be established at two levels — the local level and the national level, Tsang told China Daily.

It requires close collaboration between the SAR agencies and national agencies, added Tsang, who is also deputy director of the National Narcotics Control Commission of the Ministry of Public Security of China.

"Looking at it from a historical perspective, we actually had a similar arrangement in colonial days whereby national agencies and local agencies worked together," said Tsang, a member of the National Committee of the Chinese People's Political Consultative Conference — China's top political advisory body.

In addition to the former Special Branch, the experience of other countries and regions around the world provides enough references for setting up a national security agency in Hong Kong, Tsang said. New York City, for instance, has its own law enforcement agencies, and they also need to cooperate with the federal agencies in matters of homeland security, Tsang said.

"Such cooperation (between national agencies and local agencies) is not something new for the world," he said. Hong Kong Chief Executive Carrie Lam Cheng Yuet-ngor went to Beijing on Wednesday to convey to the central government the Hong Kong communities' opinions on the proposed law.

The central government has promised to listen to the views of Hong Kong people by inviting legal experts and Hong Kong deputies to the nation's top legislature and top advisory body to seminars to be held in Shenzhen and Beijing.

Tsang believes the central government will be responsive to the opinions from Hong Kong, and the nation has an abundance of talents to draft the law. Tsang said he understands that a lot of preparation must be made for the proposed legislation for Hong Kong, so how long the process will take remains uncertain.