SINGAPORE - More than 1,000 OCBC Bank customers called the bank's contact centre for help after it experienced on Saturday (Sept 1) night its first service outage in seven years.

A technical problem on Saturday night caused "network issues" that affected the bank's automated teller machines (ATMs), online banking system, 24-hour hotline and credit card transactions.

Responding to queries from The Straits Times on Sunday (Sept 2), Ms Koh Ching Ching, OCBC head of group brand and communications, said: "We are investigating the root cause of the technical problem.

"The problem resulted in the service disruption of our banking channels such as ATMs, online banking, and credit card transactions," she added.

Customers who tried to log into their online banking accounts were unable to access the system as the login page appeared to have trouble loading.

Disruption to services began intermittently at 8.45 pm on Saturday night. ATM services were restored by 11.32 pm, while all banking services were back to normal by 12.30 am, the bank said.

OCBC customers last experienced an outage on Sept 13, 2011 - a technical glitch had affected their ability to carry out transactions at the bank's ATMs islandwide as well as on its various Internet-banking platforms for more than four hours.

The glitch prevented the "core banking system from connecting properly to the various front- end banking systems", OCBC had said then.

That resulted in a reprimand on Oct 31, 2011 from the Monetary Authority of Singapore (MAS).

The MAS, in its review back then, said it "established that the bank did not implement sufficient measures to address single point of failure in its system and network infrastructure.