NAB says internet banking services restored after outage

National Australia Bank is investigating after customers reported difficulty accessing their online banking services.

A NAB spokesperson said the issue was impacting some services tonight, including the mobile app, internet banking and NAB Connect.

"We're sorry for the inconvenience this is causing," a spokesperson said.

"Our tech team is currently investigating and working to fix this as soon as possible."

Shortly before 9pm AEDT, the company said the services were back online.

"We apologise for the inconvenience and thank you for your patience while we resolved the issue," the bank said.

According to website Down Detector, customers started reporting issues with their service after 7pm.

While some customers reported their internet banking service was returning to normal, others had to wait longer.