No government agencies or critical information infrastructure here were affected by the cyber attacks that hit nearly 100 countries, the Cyber Security Agency of Singapore (CSA) said yesterday.

"To date, no government agencies or critical information infrastructure (CII) in Singapore have been affected by the global hacking attacks (on Friday night)," Mr Dan Yock Hau, director of the National Cyber Incident Response Centre, said in a media release.

The CIIs have been notified to be on heightened alert, he added.

The CSA advised affected organisations, businesses and members of the public to seek help from its Singapore Computer Emergency Response Team (SingCERT) at singcert@ csa.gov.sg or its hotline on 6323-5052.

All Windows users should make sure their computer systems are fully patched, the agency added.

Users should ensure that their anti-virus software is updated with the latest malware definitions, perform file backups and store them offline in case they need to restore their systems following an attack.

A fast-moving wave of cyber attacks swept the globe on Friday, apparently exploiting a flaw exposed in documents leaked from the US National Security Agency.

The malware's name is WCry, but analysts were also using variants such as WannaCry, AFP said.

The attacks used a technique known as ransomware that locks users' files unless they pay the attackers a designated sum in the virtual currency bitcoin. It has the ability to automatically spread across large networks by exploiting a known bug in Microsoft's Windows operating system.

Researchers with security software maker Avast told Reuters they had observed 57,000 infections in 99 countries, with Russia, Ukraine and Taiwan the top targets.

Chew Hui Min