Commonwealth Bank has sustained a major outage with critical services including online banking, unavailable.

A bank spokesperson told ACM, "An issue today affecting some of our services is currently being fixed".

"CommBank banking services, including payments, online access and ATMs are being restored," the spokesperson said.

"We apologise for any inconvenience and thank you for your patience."

A statement on the bank's website said it was "urgently working to fix" the issues.

ACM understands that some ATMS are offline and branches have shut down.

The bank's app is offline, with customers venting their anger online.

One person complained they "couldn't even buy groceries" another said the bank wanted to go "full digital but cash was king".

A third wrote: "Commbank app must be stuck

See Full Page