Another ANZ customer, Jessica Ahsee, said she was stuck at the supermarket and unable to pay for groceries because of ANZ's problems.

"I got stuck at the supermarket because couldn’t transfer money to pay for my groceries that I caught a 30-minute bus trip to get," Ms Ahsee said.

The bank is unable to say when services will be back to normal. The outage began before noon on Thursday.

However just after 4pm ANZ tweeted: "our systems are slowly coming back up for most of our customers. If you’re still experiencing issues, please try again a bit later. Thanks for your patience and we're very sorry again for all the inconvenience caused".

An ANZ spokesman said a "technical fault" was to blame for the outage affecting internet banking, goMoney and the ANZ app.

"We have a team of experts currently working on this as a top priority and we’re doing everything we can to restore these systems as soon as possible," the spokesperson said.

"We apologise for the inconvenience this will cause our customers."