Several UK financial institutions have been hit in the last six months by cyber-attacks, some of which have disrupted services, according to the Bank of England.
The losses from these attacks have been relatively small so far but have exposed vulnerabilities which, if exploited, could be of "significant cost" and "borne by a large number of institutions", according to the BofE Financial Stability Report.
The report also highlights the extent to which cyber-crime is moving up the agenda for banks. A quarter of respondents to the bank's most recent systemic risk survey highlight operational risk as one of the main threats to UK financial stability. More than half of the 25% specifically cite risks from cyber-attacks - a problem barely mentioned just a year earlier.
The BofE says that it welcomes the progress being made by the government, regulators and industry players in drawing up a shared programme to assess, test and improve defences.
Among the most eye-catching initiatives undertaken so far was the 'Waking Shark II' war games operation earlier this month, where hundreds of employees from dozens of financial institutions across London scrambled to deal with a host of simulated cyber-attacks. A report on the operation will be published early next year.
The bank also reiterated that it expects concrete action plans in place by the first quarter of next year to deliver a "high level of protection" for core financial institutions.
Chris McIntosh, CEO of vendor ViaSat UK says: "The financial sector is the custodian of millions of customer details and the gateway to billions of pounds. Unless this sector takes the right action, we will see attacks become more refined and sophisticated with massive repercussions for this sector and the wider economy."