Hong Kong’s parliament has passed a controversial national security law granting the government more power to quash dissent, widely seen as the latest step in a sweeping political crackdown triggered by pro-democracy protests in 2019.

Critics of the safeguarding national security law, also known as article 23, say it will further erode the city’s rights and freedoms and usher in a new era of authoritarianism.

Under the law, treason, insurrection and sabotage can be punished with life sentences, while jail terms for sedition are increased from two years to seven, or 10 if alleged perpetrators are found to have colluded with a foreign force. The law also lengthens allowable periods of detention without charge from 48 hours to two weeks.

The bill was rushed through the legislative council in two weeks after being open for community consultation for just 30 days. It was passed unanimously on Tuesday by the 90-seat chamber, which is made up almost wholly of pro-Beijing establishment legislators. All but one sitting member spoke during the seven-hour debate on the second reading.

The UN rights chief, Volker Türk, denounced the “rushed” adoption of the law, which he said was “a regressive step for the protection of human rights”.

The UK Foreign Secretary, David Cameron, said the law would have far-reaching implications and further damage the rights and freedoms of people in Hong Kong. Britain, the former colonial power in Hong Kong, has been increasingly critical of moves by China to suppress dissent.

“The overall impact of Hong Kong’s new national security law is that it will further damage the rights and freedoms enjoyed in the city,” Cameron said in a statement. “The broad definitions of national security and external interference will make it harder for those who live, work and do business in Hong Kong.”

A US State Department spokesperson said the bill could accelerate the closing of a once open society and it was analysing the potential risks to US citizens and American interests.

Hong Kong’s chief executive, John Lee, heralded the passage of the law, which he said was it was “needed to guard against people who invade our home”. Because of its passing, he claimed, Hong Kong “no longer need to worry about people destroying public infrastructure”.

“We need to have such tools which are effective in guarding against black violence and colour revolution,” he said, using terms commonly heard from Hong Kong and Chinese authorities to describe protesters as violent and driven by outside influences.

He said the law would be signed and gazetted and come into force on Saturday.

Hong Kong’s security chief, Chris Tang, dismissed concerns that the law removed from the definition of sedition that it was constituted by an incitement of violence, the South China Morning Post reported. “Although these acts do not always involve violence, ignoring such seditious acts will give rise to more violent actions,” he said.

Maya Wang, the acting China director at Human Rights Watch, said the law would “usher Hong Kong into a new era of authoritarianism”.

Amnesty International’s China director, Sarah Brooks, described the law as “killing off any remaining shred of hope that public outcry could counter its most destructive elements”.

“The passing of this law sends the clearest message yet that the Hong Kong authorities’ hunger to accommodate Beijing’s will outstrip any past commitments on human rights,” Brooks said.

Pro-democracy activists also criticised the law. “All the years of advocacy for or defence of Hong Kong’s rule of law, democracy and human rights have been for nought, blown away by a darkness that contains not even a speck of light,” said Kevin Yam, an Australia-based Hong Kong lawyer and activist, on X.

Also on X, Nathan Law, a UK-based activist, said the law was a sign of civil society’s further collapse. “The vague laws empower the government to arbitrarily label anyone as a ‘foreign agent’. Journalists are targeted as a ‘state secret’ can be almost anything,” he wrote.

Yam and Law are subject to controversial arrest warrants issued by Hong Kong, over their activism.

Article 23 is named for the section of Hong Kong’s mini-constitution, established after the city was handed over from British control in 1997, that requires the government to create domestic national security laws. An attempt in 2003 failed amid widespread community backlash and protest. In 2021 Beijing imposed the national security law (NSL) on Hong Kong, citing Hong Kong’s failure to introduce article 23.

That law was used to crush the remaining elements of the 2019 pro-democracy protests and political opposition. Scores of pro-democracy activists and politicians have been jailed under the NSL, and the legal and political system has been overhauled to ensure that only those who Beijing deems to be “patriots” can govern Hong Kong.

The proposed law is similar in scope and detail to the NSL, but the NSL will remain, and take precedence over Article 23, according to previous statements by the Hong Kong government.

Concerns raised by the UK foreign secretary, David Cameron, were rejected last month as “maliciously smearing and attacking Hong Kong’s human rights, freedoms and rule of law”.