ING Australia customers have been left in the lurch at checkouts across the country with a major system outage affecting mobile and electronic services.

Customers have taken to social media to vent their frustration at the bank, with many left stranded at checkouts, restaurants and petrol stations.

The ‘unexpected outage’ is affecting the online banking, mobile app and phone line services.

A statement on ING Australia’s Facebook page said the organisation did not know when the situation would be rectified.

“Hi there, just letting you know we’re experiencing an unexpected outage on our online banking, mobile app, phone line service. We’re sorry for the inconvenience this is causing,” the statement said.

“Our IT team are investigating it right now and we hope to have the service back up and running as normal soon. At this stage there is no ETA but we will keep you updated with any news.”

Angry social media users have been swift to criticise the bank, with some reporting being stranded while being unable to pay for goods and services.