Two-thirds of UK banks and insurance firms have little confidence their systems will remain secure in the event of an IT failure.
Just one third of 176 polled organisations said they were certain security could be maintained in the event of an outage while respondents admitted that customer account access and online uptime could also suffer.
The Fujitsu-commissioned study of IT decision makers in UK retail and investment banks insurance firms also discovered that security concerns are holding banks back from adopting new technologies like cloud and mobile.
Anne MacRae, head of Financial Services for Fujitsu UK, said: "It's troubling to see the low confidence from financial services companies around their ability to withstand IT failures.
"This is an issue that we've seen affect several organisations in recent months and which has significantly disrupted business continuity. Going forward, effective steps must be taken to ensure that this risk is controlled."
A total of 52% of respondents conceded that security was a barrier to successful mobile banking strategies, 45% of organisations have not even dipped a toe into the cloud, despite expressing enthusiasm.
"The financial services industry has faced some tough challenges recently and will continue to do so over the coming years", added MacRae. "Technologies like cloud and mobile can be transformative, and security strategies should be embraced, which allow financial services firms to capitalise on their potential."