It was human error during maintenance works that caused the islandwide Nets service disruption on Feb 2, and not any systemic risk or security issues, the e-payment giant said in a statement yesterday.
"We have completed investigations into the cause of the incident and concluded that it resulted from an inadvertent human error during system maintenance, which disrupted Nets EFTPOS (Electronic Funds Transfer at Point Of Sale) connection to our participating banks," said the statement.
Nets said that such an error should not have occurred and apologised for the disruption.
It had informed consumers about the hour-long outage in a Facebook post at about 2.25pm that day.
Services were restored at 3pm and have since been functioning normally.
Following the incident, the Monetary Authority of Singapore (MAS) issued a statement saying that it takes a serious view of all incidents affecting the availability of critical payment systems, such as the EFTPOS services operated by Nets.
MAS instructed Nets to submit a thorough investigation report to the authority, which said that supervisory action may be taken after a review, if necessary.
Nets yesterday said that it has submitted its investigation report to MAS.
It has also engaged an independent consultant to validate and further enhance its processes to prevent the recurrence of similar incidents.
Owned by DBS Bank, OCBC Bank and United Overseas Bank, Nets runs the country's oldest and most ubiquitous system, dubbed Electronic Funds Transfer at Point Of Sale.
This 30-year-old cashless payment scheme lets consumers use their ATM cards for direct deductions from their bank accounts at about 100,000 acceptance points islandwide, including those at Cold Storage and FairPrice supermarkets.