BEIJING - China's top lawmaking body on Tuesday (March 30) unanimously endorsed sweeping electoral reforms in Hong Kong that will nearly halve the number of legislators directly elected by the public.

According to the amended annexes of the Basic Law, Hong Kong's mini Constitution, only 20 members of the expanded 90-member - from the current 70 - Legislative Council (LegCo) will be directly elected by Hong Kongers, down from the current 35.

The Elections Committee, in charge of picking the city's leader, will be expanded by 300 to 1,500 members and will be given powers to pick 40 LegCo members. The remaining 30 members will come from functional constituencies - members picked to represent professionals in sectors ranging from law and education to construction.

A committee in charge of vetting all potential office holders will be led by officers from the national security department of the city's police force. They will then be reviewed by the Committee for Safeguarding National Security, chaired by the territory's chief executive, the amended legislation stated, adding that decisions are final.

It is unclear how big the committee will be, but local media has reported that there will be fewer than 10 members.

According to the official Xinhua news agency, Chinese President Xi Jinping has signed off on the amendments, voted for by 167 members of the National People's Congress Standing Committee.

"The meeting of the Standing Committee of the National People's Congress has just ended, and the amendments… were passed unanimously to warm applause," the city's sole representative, Mr Tam Yiu-chung, told The Straits Times in a text message.

The changes will go into effect from Wednesday (March 31).

"These changes are to realise what we have been referring to as 'patriots ruling Hong Kong'," Mr Tam said, during a Facebook live session after attending the meeting.

The amendments have closed loopholes in the current system while guaranteeing a "solid foundation" for the implementation of the "one country, two systems" principle, the cabinet-level Hong Kong and Macao Affairs Office said, in a statement that echoed earlier comments.

This was repeated by China's foreign ministry, which said the "improvements" to Hong Kong's electoral rules are to create a political system that better reflects the conditions of the city today and all strata of society.

"Any attempt to intervene in China's affairs and put pressure on China will never succeed," it added.

These changes will now be promulgated in Hong Kong - which means the rules have to be adopted immediately, bypassing the local legislature.

Officials insist this is to prevent "foreign interference" in the city's politics, which Beijing claims has been infiltrated by foreign forces who aim to sow chaos in the territory and, by extension, China.

Since the handover in 1997, the former British colony has been governed under the "one country, two systems" principle, which allows for a separate legislative, judiciary and executive from the mainland, and promises a "high level of autonomy" until 2047.

But in recent years, there has been a growing frustration with a government many see as incompetent in dealing with bread-and-butter issues, compounded by the fear that Beijing was encroaching on the city's relative freedom.

It resulted in historic and, at times, violent protests in 2019 that crippled the territory and infuriated Beijing.

The electoral revamp, emphasising the need for "patriots ruling Hong Kong", is the latest in a series of moves in response to those protests.

Last year, a sweeping national security law was implemented in a similar manner, dealing a body blow to the city's hopes for democracy.

The United States, Britain, Japan and the European Union have all condemned China's moves, with the Joe Biden administration this month tightening sanctions imposed last year by then President Donald Trump against key officials.

US Secretary of State Antony Blinken has called the recent overhaul of the city's electoral system a "direct attack" on the autonomy China promised to Hong Kong, while British Foreign Secretary Dominic Raab has said the "radical changes" constitute another breach of the 1984 Sino-British Joint Declaration that paved the way for the city's return to Chinese rule in 1997.