Hong Kong on Tuesday passed national security laws at the behest of Beijing, thwarting decades of public resistance in a move that critics say will strike a lasting blow to the partial autonomy the city had been promised by China.

The new legislation, which was passed with extraordinary speed, grants the authorities even more powers to crack down on opposition to Beijing and the Hong Kong government, establishing penalties — including life imprisonment — for political crimes like treason and insurrection, which are vaguely defined. It also targets offenses like “external interference” and the theft of state secrets, creating potential risks for multinational companies and international groups operating in the Asian financial center.

Analysts say the legislation, which will take effect on March 23, could have a chilling effect on a wide range of people, including entrepreneurs, civil servants, lawyers, diplomats, journalists and academics, raising questions about Hong Kong’s status as an international city.

Many of the opposition figures who might have challenged the legislation have either been jailed or have gone into exile since China’s ruling Communist Party, under Xi Jinping, its most powerful leader in decades, imposed the first national security law, in 2020. That law gave the authorities a powerful tool to quash dissent after months of antigovernment demonstrations engulfed the city in 2019.

Hong Kong’s Beijing-backed leader, John Lee, has said the package of new laws is needed to root out unrest and to fight what he described as Western spying. Once the laws are passed, he has said, the government can focus on the economy.

In a speech at the legislature, Mr. Lee said that the new laws would “allow Hong Kong to effectively prevent and put a stop to espionage activities, the conspiracies and traps of intelligence units and the infiltration and damage of enemy forces.”

Lawmakers had put the legislation on the fast track, holding marathon sessions over a week and working through a weekend. The bill was passed unanimously on Tuesday.

“A rapid passage is meant to show people in Hong Kong the government’s resolve and ability to enforce it,” said Steve Tsang, director of the SOAS China Institute in London. “The new national security bill is as much about intimidation as it is about enforcement.”

For Mr. Lee, the Hong Kong leader, “the first concern is not how people in Hong Kong or in the rest of the world see this,” Professor Tsang said. “He is performing for the audience of one — Xi himself.”

And in the eyes of Beijing, these laws are long overdue.

When Hong Kong, a former British colony, was returned to Chinese rule in 1997, it was given a mini-constitution designed to protect civil liberties unknown in mainland China, such as freedom of expression, assembly and the media. But China also insisted on a provision called Article 23, which required Hong Kong to draft a package of internal security laws to replace colonial-era sedition laws.

The first attempts to pass such legislation, in 2003, set off mass protests involving hundreds of thousands of people. Top officials resigned, and in the years that followed, city leaders were reluctant to raise the matter again, for fear of public backlash.

But in recent months, the Chinese Communist Party has urged the Hong Kong government to enact Article 23 laws.

There was little chance that China’s will would not be heeded; Hong Kong’s legislature has been overwhelmingly stacked with pro-Beijing lawmakers since China overhauled the electoral system to exclude candidates who aren’t considered “patriots.”

The new laws take aim at five types of offenses: treason, insurrection, theft of state secrets, sabotage and external interference. They also introduce key changes to due process. In some instances, the police may now seek permission from magistrates to prevent suspects from consulting with the lawyers of their choice, if that is deemed a threat to national security.

Human rights groups said that in swiftly passing the law, the authorities had reversed course on the freedoms once promised to the city.

Maya Wang, the acting China director at Human Rights Watch, said on Tuesday that the new security law would “usher Hong Kong into a new era of authoritarianism.” The government has criticized rights advocacy groups based overseas as “anti-China” and “anti-government” organizations.

The vague wording of some of the legislation has raised questions among legal scholars. For example, an act of espionage, under the new laws, could include passing “useful information” to an “external force.” Such a broad definition could discourage legitimate exchanges with diplomats, Simon Young, a law professor at the University of Hong Kong, wrote in a submission to the government last month.

Professor Young also objected to the legislation’s sweeping definition of “sedition,” which includes an intent to “bring disaffection” against the state or its institutions. Disaffection is “an emotional state of too low a threshold to be the subject of a crime,” he wrote.

“It is not a crime to simply feel this way,” he added.

The legislation also empowers the city’s leader, known as the chief executive, to make new, related laws, which can carry penalties of up to seven years in prison, without going through the legislature. The leader would consult the cabinet before enacting any such law; the legislative council, known as the LegCo, would be able to amend or reject the law later.

Such a mechanism would not be new to Hong Kong, but it raises the potential for abuse, given how broadly written the new legislation is, said Thomas E. Kellogg, the executive director of the Center for Asian Law at Georgetown University.

“This is deeply disturbing,” Professor Kellogg wrote in an email. “The LegCo is handing the chief executive the power to expand the law even further, in ways that could further infringe on basic rights.”

Hong Kong, known just a few years ago for its boisterous political opposition, now more closely resembles mainland China, where dissent can carry a high cost. During the recent sessions over the new security legislation, lawmakers mostly suggested changes that would make it even tougher.

“They seem to be looking for ways to signal their fealty to the government’s national security agenda, and to ensure that they are demonstrating no daylight between themselves and the government,” Professor Kellogg said.

Discussion of the bill illustrated the city’s new political landscape and the murkiness of the new boundaries around speech.

Lawmakers asked if possession of old copies of Apple Daily, a now-defunct pro-democracy newspaper, would be an offense. (A security official said it would depend on whether there was “seditious intent.”) A government adviser said that priests who heard confessions about national security offenses like treason could themselves be charged under the new law if they did not report what they heard. (The Catholic Diocese of Hong Kong said the church recognized that citizens had an obligation to ensure national security, but that confessions would remain confidential.)

The legislation’s vague wording — for example, in how it defines offenses like the theft of state secrets — is comparable to language found in security legislation in mainland China. And someone who shares “information that appears to be confidential matter,” even if it is not classified as a state secret, could be punished if that person intended to endanger national security, in the eyes of the authorities.

Business leaders in Hong Kong say such changes could raise the cost of operating in the city by requiring companies to scrutinize documents and other information shared by employees, to ensure that they do not inadvertently violate the new law.

One risk is that Hong Kong’s comparative business advantage over the mainland could be eroded, said Johannes Hack, the president of the German Chamber of Commerce in Hong Kong.

“Part of the unique value Hong Kong has for Western (German) stakeholders is the openness of the city, and we feel the balance between openness and the desire for security needs to be well calibrated,” he wrote in a message on WhatsApp.

Olivia Wang contributed reporting.