BANGKOK--Singapore’s more than four million residents will have to use facial verification technology to access government services through the national identity scheme, a move criticized as intrusive and heavy-handed by privacy advocates.

Facial verification, which works by scanning someone’s face and matching it with a database image, is already used widely to unlock smartphones and access bank accounts, but Singapore is the first state to use it in a national ID scheme.

“Unlike the use of biometrics for surveillance, it ensures that the user is aware and that their explicit consent is sought before proceeding with the verification process,” a spokeswoman for the Singapore government technology agency GovTech said.

“The system is designed with their privacy in mind.”

The facial verification identity check on SingPass, the national digital ID that allows access to more than 400 public and private services, is being piloted by several government agencies at kiosks for users without smartphones, she added.

Worldwide, facial recognition systems are being deployed for a range of applications from tracking criminals to counting truant students.

In Singapore, facial recognition technology is being rolled out at the airport and even on lampposts.

Andrew Bud, chief executive of iProov, the British firm that supplied the technology to Singapore, said the city-state’s decision to use it in the ID scheme “marks a tipping point.”

“The rest of the world will study this innovation,” he said.

Digital rights campaigners, however, said the inclusion of the technology raised concerns about privacy and surveillance.

Ioannis Kouvakas, a legal officer at digital rights group Privacy International, said the fact that the SingPass system relies on consent does not make it “less intrusive.”

“It still processes extremely sensitive biometric data. The imbalance of power between governments and citizens, the lack of flexibility and involuntariness renders the consent invalid,” he told the Thomson Reuters Foundation.

“There’s nothing benign in a form of surveillance which is unprecedentedly intrusive and has been found several times to misidentify or even target people of color and women,” he said.

He added that using facial verification to unlock a phone is “completely different” from a national ID scheme forced by a government on its citizens, carrying the risk of discrimination and exclusion of minorities and vulnerable people.

The GovTech spokeswoman said the SingPass facial verification technology collects only the data that is needed for a specific purpose, and the selfie is retained on government servers for only 30 days.

No personal data is shared with the private sector--only a matching score when the facial image is verified against the government biometric database, she added.