Chinese lawmakers on Saturday pressed forward with a contentious draft security law for Hong Kong, signaling that they would soon pass the legislation, which would deepen the Communist Party’s domination of the territory.

A meeting in Beijing of the National People’s Congress Standing Committee — a select body of lawmakers who can create legislation — undertook “initial deliberation” of the draft security law this week, Tam Yiu-chung, a member of the committee, told RTHK, the Hong Kong news broadcaster.

Mr. Tam said the committee would not vote on the law during the session, which was to end Saturday, leaving that for a later meeting.

The first official report on the Standing Committee meeting from Chinese state media did not mention the Hong Kong security legislation. But Hong Kong news outlets, including Ming Pao and The South China Morning Post, said the legislation had not gone to a vote on Saturday.

Even so, a vote is likely soon. Chinese news media and law experts have said that the government is eager to bring the law into force quickly.

“This legislation about Hong Kong that every side is focused on has hopes of taking effect within a short time,” Tian Feilong, an associate professor of law at Beihang University in Beijing who studies Hong Kong, said in an online article about the law on Saturday. “Hong Kong local forces and external interventionist forces are stepping efforts up to sabotage the legislation.”

In the wake of monthslong protests in Hong Kong last year over a proposed extradition bill, Chinese Communist Party leaders in October demanded steps to “safeguard national security” in the territory, a former British colony that retained its own legal system after returning to Chinese sovereignty in 1997.

Last month, the full, annual session of China’s National People’s Congress nearly unanimously passed a resolution that authorized the Congress’s Standing Committee, which meets more regularly, to impose security legislation on Hong Kong. That will be achieved by adding new rules to an annex of the Basic Law, the foundational law that gives Hong Kong special status.

There is virtually no doubt that the Chinese lawmakers — handpicked by the ruling Communist Party — will ultimately approve the legislation by overwhelming numbers. Chinese rules say that draft laws should be discussed at three, perhaps two, lawmakers’ sessions before a vote. This was only the first time the lawmakers had discussed the proposed security law.

Chinese legislation is often released for public comment before lawmakers vote on it. But it was unclear on Saturday whether the draft Hong Kong law would be made public.

A spokesman for the legislative committee said on Thursday that the proposed law would define crimes of separatism, subversion, terrorism and “colluding with foreign powers.” Critics say those sweeping categories are likely to be used to repress dissent in Hong Kong, where residents have enjoyed far more freedom than people in mainland China do.

The provision on collusion — added since the outlines of the law were released in late May — could be used to arrest and convict Hong Kong residents for working with foreign governments and groups, said Michael C. Davis, a former law professor at the University of Hong Kong who is a research scholar at Columbia University.

“Collusion with foreigners can then be obviously targeting the locals that are going to Washington and London” to seek support, Mr. Davis said by telephone. “The terms that are being identified as crimes are vague terms, poorly defined, and China has never defined these terms in a way that’s reliable.”

Existing rules ensure that the council is dominated by lawmakers loyal to Beijing, but a minority of pro-democracy lawmakers has kept a foothold in it. Pro-democracy and pro-Beijing politicians in Hong Kong have said that the security law might be used to disqualify at least some opposition candidates from running in the elections.

On Friday, the United States secretary of state, Mike Pompeo, signaled that the Trump administration would use the September elections to judge whether and by how much to reduce Hong Kong’s special access to American markets. He and other administration officials have said that the pending security legislation shows that China no longer respects Hong Kong’s autonomy.

“We should all watch very closely whether those elections are permitted to take place in a free and fair fashion,” Mr. Pompeo said in a video speech on Friday. “President Trump has made very, very clear to the extent that the Chinese Communist Party treats Hong Kong as it does Shenzhen and Shanghai, we will treat them the same.”

The Chinese government and officials in Hong Kong have asserted that the national security law enjoys broad support in the city, a position that pro-democracy politicians and protesters have contested.

On Saturday, 30 unions and a student group held what they described as a referendum, to gauge their members’ support for a strike in opposition to the law. The unions represented accountants, retail employees, civil servants and bartenders, among other workers.

Organizers set up polling stations across Hong Kong in what was partly an attempt to muster a show of numerical force. The massive street marches last year that demonstrated the breadth of antigovernment sentiment have since dwindled, due in part to the Covid-19 pandemic and increased police pressure on the protests.

The Hong Kong government has fiercely denounced the unions’ referendum, singling out the civil servants’ union in particular for criticism. In a statement on Saturday, a government spokesman called the strike proposal “absolutely unacceptable” and said it would “seriously tarnish” the reputation of the civil service.

Alex Tsui, the head of a union of hotel workers, said the vote was a way to challenge the government’s claim that the national security push was widely popular. “It’s not, but how can we prove it? By voting,” he said.

Vivian Wang contributed reporting.