Furious NAB Bank customers have been struck by a major tech outage impacting its internet, mobile and desktop banking services.

More than 1900 complaints were made to tech monitoring website Downdetector by 4.30pm Thursday by frustrated customers who couldn’t use the bank app and other online services.

A NAB spokesperson told Daily Mail Australia at 6.39 pm that its services were up and running again.

The first reports of NAB services being down came in around 3.50 pm, according to Downdetector.

It’s the second major tech outage to hit bank in the past two months.

‘Currently NAB’s systems experiencing a technical issue which is affecting the functionality of the NAB App and Internet Banking,’ the bank tweeted earlier on Thursday.

‘Please allow some time as our support teams are working hard to fix this. We appreciate your patience & apologize for the inconvenience.’

Angry customers took to social media to vent their frustrations.

‘Is there a problem with internet banking? Really slow to login and once in, immediately thrown out,’ one customer tweeted.

Another wrote: ‘Has internet banking been hacked ? Asking for a New Version of online banking but won’t work,’ another X user wondered.

A third added: ‘(What) the f**k is wrong with NAB internet banking?’