The National Australia Bank has promised to compensate customers who suffered financial losses during a nationwide outage that downed mobile banking, ATMs, EFTPOS and other services for several hours on Saturday.

The Australia-wide outage began impacting customers about 8am on Saturday, with hundreds of customers taking to Twitter to complain they could not pay for groceries, petrol, taxi fares or keep appointments.

By midday, the bank announced some of its services were starting to come back online.

“It looks like our ATMs and EFTPOS services are coming back online. We’re still working on restoring our Internet & mobile banking. Really sorry for interrupting your Saturday everyone”.

And by 1.30pm on Saturday, NAB announced that the mobile app for internet banking was still out.

“Our services including Internet Banking, ATMs and EFTPOS appear to be back online. We’re still working to restore the mobile app. Really sorry again for spoiling your Saturday”.

Most services have now been restored after the major outage, which was caused by a series of faults originating from a power failure.

NAB Business executive general manager Cindy Batchelor told reporters in Melbourne on Saturday afternoon that “if there was a loss that was driven by the outage today then compensation will be provided to customers”

“We’ll work with each and every one of them to understand exactly what happened to that particular customer,” she said.

Furious customers took to social media after being forced to change Saturday appointments, many finding themselves stranded at supermarket checkouts and petrol stations due to the outage.

It looks like our ATMs and EFTPOS services are coming back online. We’re still working on restoring our Internet & mobile banking. Really sorry for interrupting your Saturday everyone.

— NAB (@NAB) May 26, 2018

NAB had earlier apologised to customers about the crash happening on a Saturday and said they were working on a fix “ASAP”.

Sorry this has happened on a Saturday everyone. Systems are still affected but for purchases only, NAB customers can use non-NAB operated EFTPOS machines, but are unable to withdraw cash.

— NAB (@NAB) May 26, 2018

NAB customer and small business operator Mark Crompton wrote on Twitter that they were unable to take card payments on their busiest shopping day of the week.

“We are a small business, in the middle of a busy Westfield shopping centre & we can not take card payments – 75% of our transactions…on the busiest trading day of the week,” he tweeted, adding the outage was a “wee bit embarrassing” after NAB chairman Dr Ken Henry’s speech talking up how the bank had great ambition for its customers.

“Not helping the economy today NAB?”

Wine industry businessman Will de Beaurepaire estimated “hundreds of millions of dollars” would be lost in revenue.

https://twitter.com/willbeaurepaire/status/1000168068901842944

“The company I work for has literally lost thousands of dollars in sales this morning because of this. And we have no ETA as to when it’ll be fixed,” another NAB customer Josh Salmon tweeted.

A Perth-based business operator tweeted: “We just saw $2500 walk out the door. But “Sorry this happened on a Saturday”, makes me feel all warm and fuzzy inside”.

Customers of NAB-owned BNZ in New Zealand faced similar problems.