The national security bill buttresses Macau's Committee for Safeguarding National Security (CDSE), which was created in 2018 to support the Chinese city's leader in security matters.

Macau has its own legal system largely based on Portuguese law but enacted national security legislation in 2009 and widened its powers in 2023.

Under the bill passed on Thursday, judges hearing security-related cases will be able to decide whether they should be held behind closed doors.

Defence lawyers involved in such cases will also be required to obtain permission from national security officials because of the possibility that some case information could be classified.

Macau's Legislative Assembly said the bill was passed unanimously.

The bill "further strengthens the top-level framework for safeguarding national security", the city's government said in a statement, and demonstrates "the successful implementation of the principle 'patriots governing Macao'".

Macau's security secretary Chan Tsz-king said last month that the bill does not seek to deprive people of their right to a defence or revoke lawyers' practising qualifications.

But analysts have warned that the regulation could undermine the functioning of government departments and the rights guaranteed by Macau's mini-constitution.

Jorge Menezes, a Portuguese lawyer who has practised in Macau, told AFP that the new legislation extended "disturbing rules applicable to specific criminal offences pertaining to national security to all sorts of cases, be it civil, administrative, or criminal".

Lawyers who fail the review are also have "no right of appeal", Menezes said.

"It will have a chilling effect on many lawyers who will tend to self-censor and 'behave', as well as a loss of transparency and oversight by the press and the community," Menezes added.

The legislation will take effect the day following its promulgation.

Macau authorities arrested former legislator Au Kam-san in July 2025 for alleged foreign collusion in the first known use of the national security law in the Chinese city.

"This (the bill) applies to Au Kam-san, a Chinese and Portuguese citizen arrested on the basis of no evidence other than political motives," said Menezes.

The European Union condemned the arrest of Au in August, saying it heightened concerns about the "erosion of political pluralism" in the Chinese territory.