China has brought into force a law that requires individuals to have their faces scanned when purchasing a SIM card in a move to ensure mobile users can be identified.
The law, which was announced in September and came into force on 1 December, is part of a broader crackdown on cyber-crime in the country.
The government said it aimed to “protect the legitimate rights and interest of citizens in cyberspace”.
Chinese citizens are already required to show a national ID card or passport and have their photo taken.
The new law requires them to have a facial scan in order to verify that they are a match for the ID provided – a practice already brought in by some telecoms providers as of last year.
The Chinese government wants to be able to identify internet users under a “real name” policy, with a 2017 law, for instance, requiring internet platforms to verify a user’s identity before allowing them to post content online.
The new mobile phone law strengthens such provisions since most Chinese users access the internet via their phones.
Face recognition is also increasingly important to police work such as tracking fugitives, with police saying last year they were able to use the technology to pick out a fugitive from a crowd of 60,000 at a concert.
But it is used increasingly often in the private sector as well, such as to pay in shops and supermarkets.
China has no regulations as yet that limit the use of the technology, leading some to push for stricter controls.
Last month Guo Bing, a professor at Zhejiang Sci-Tech University, filed what is believed to be the country’s first lawsuit against face recognition.
He alleged that a safari park in Hangzhou violated consumer protection laws by scanning his face without his consent.
China’s education ministry said in September it would “curb and regulate” the use of face recognition after parents were angered by its use at a university in Nanjing to monitor students’ attendance and whether they paid attention during class.
Activist group Human Rights Watch said the new law moved China further toward a “dystopian surveillance state” where citizens are constantly monitored.
Some users also expressed unease about the spread of face recognition, saying data breaches could put the data into the hands of thieves.
“Before, thieves knew what your name was, in the future they’ll know what you’ll look like,” said one user of the Weibo microblogging site.
But others said they hoped it could provide protections against scammers, with another Weibo user writing, “As someone who has had their identity stolen, I feel relieved.”