Tesco Bank customers have been unable to access their online accounts in the second IT glitch in as many days for the company.
The latest issue affected current accounts, savings products and credit cards from mid-morning until early afternoon on Wednesday.
On Tuesday, thousands of Tesco grocery customers had their home deliveries cancelled or postponed following a computer glitch.
A spokesman for the bank said the failure was the result of a technical issue and was unrelated to Tuesday's issue.
He said: "We apologise to customers who could not access online banking earlier today.
"Service is now restored and customers can access their account as normal."
The grocery delivery problem began on Tuesday morning and was centred on customer orders and fulfilment from some stores.
A spokesman said less than 10% of customers were affected.