Tesco Bank customers are still unable to log into accounts following a migration glitch.
Customers faced difficulties logging into accounts earlier in the week when Tesco Bank systems crashed as it migrated savings and loans accounts from in-house systems at its former partner Royal Bank of Scotland (RBS). The company said the process was complete and its online banking system had returned to normal service.
But a spokesman for Tesco Bank confirmed some customers were still experiencing difficulties.
"The majority of customers are able to access their accounts. However, we know there are some customers that have not been able to logon. These customers should go to the online banking page for additional support," said Tesco Bank.
"We have significantly increased the number of callcentre staff available to help customers access their accounts. We are working hard to resolve any remaining issues that our customers have as quickly as possible," the bank added.
Tesco set up its own core banking system in November 2009, when it selected an off-the-shelf core banking system from Fiserv in its move to becoming a retail bank. Tesco Bank went live with the system about 11 months later.
Tesco Bank's efforts to improve technology as a key driver for growth in the UK and overseas prompted an increase in Tesco's capital expenditure last year. Capital expenditure in the UK was £1.7bn, with an additional £200m in the group's banking arm.