The outage went on for over two hours on Monday, during which customers could not access their online banking service and were also not able to withdraw money through ATMs. The telephone and banking application services were also down.
Standard Bank personal and business banking CEO Funeka Montjane said: "We experienced a hardware failure in one of our mainframes.
"We worked as fast as possible to restore the services but you have to do it in an orderly way so you don’t lose transactions in the process."
However, customers complained of experiencing problems even after the bank claimed of resolving the issues.
The bank confirmed that it had restored its banking services, but mobile banking apps are still unavailable.
Standard Bank said: "We are working to get these up & running, apologies for the inconvenience."
The incident comes a week after First National Bank faced problems with its payroll deposits and double debits.
