Frustrated National Australia Bank customers have been unable to access their accounts after online banking services went down across the country this afternoon.

Customers took to social media to vent their anger, with some threatening to change their bank after what they claimed was the latest in a series of issues with accessing their online accounts.

“Look this is more than just an inconvenience as i cannot access my money which i need to go grocery shopping to be able to feed myself for the next week and to be able to purchase fuel to get to work to make money,” one person posted.

“I’m thinking there might be a better bank out there for me”.

The bank has sent messages to customers apologising for the outage, which is affecting internet banking and the mobile app.

“Our tech teams are working to fix Internet Banking and the Mobile App as quickly as possible,” the message said.

“Telephone banking, ATMs and Eftpos services are all working as normal”.

Online services were restored about 3.30pm. The bank has not said what caused the problem.