National Australia Bank customers across the country were left locked out of their accounts and unable to access internet banking after the bank’s online services were hit by an unknown technical issue.

More than 1000 NAB customers reported issues with their internet banking since 1pm AEST on Monday, and the problems occurred across the country, according to outage website DownDetector.

“We’re aware of an issue currently impacting some of our services including internet banking, mobile and desktop,” a NAB spokeswoman told this masthead.

“We’re sorry for any inconvenience this is causing. Our tech team is investigating and working to fix this as soon as possible. We are continuing to keep our customers updated via banners in our digital banking channels and across social media.”

NAB said at 10pm on Monday that the issues had been resolved.

The bank has been contacted for further comment.

The outage comes about a month after NAB rival ANZ suffered an hours-long incident affecting its systems. It later blamed an unnamed “third party vendor” for the problems.

It also comes about six months after a mass Optus network outage that lasted 13 hours and affected more than 10 million people nationally, along with 400,000 businesses.