The Office of the Privacy Commissioner for Personal Data (PCPD) said on Thursday that it has launched a compliance check after receiving a data breach notification from the Consumer Council.
The council announced on its website that services such as complaints and enquiry hotlines have been affected because of a "system disruption" on Wednesday, but did not elaborate further.
The privacy watchdog urged people to protect their data by changing the passwords of online accounts, keeping an eye on unusual logins of personal emails or accounts, and looking out for suspicious calls or text messages.
"Having considered that the incident may involve the leakage of personal data, the PCPD appeals to the possibly affected data subjects to be vigilant about potential theft of their personal data. If they are in doubt about whether their personal data have been leaked, they may make enquiries with the relevant organisation or the PCPD," it said in a statement.
It also advised organisations which handle personal data to conduct regular risk assessments and establish clear internal policies on data governance.