Customers across the country were unable to use Swedbank's online banking service early on Monday, with the bank urging those who needed to make urgent transactions to use telephone banking instead.
The bank's Facebook page was full of complaints, with some customers also reporting that they had experienced difficulties withdrawing money from ATMs in Sweden.
Swedbank posted an update on Facebook at 9.23am, stating that all customers' bank cards should be working. An hour later it posted an alternative link to allow customers to bank online.
By 11am the bank's website was up and running.
"All services are working again," read a statement on the site.
"We apologize for any inconvenience."
Swedbank is Sweden's largest bank in terms of customers, with eight million private customers and more than 600 000 corporate customers.
The bank is one of the most popular with foreigners living in Sweden, as it offers online information in English.