Foreign exchange firm Travelex confirmed its systems were take offline after a software virus was discovered on New Year’s Eve.
Action to take down the company’s website was made as a “precautionary measure” to protect data and prevent the spread of the virus.
Travelex UK said: “Our investigation to date shows no indication that any personal or customer data has been compromised.
“The company’s network of branches continues to provide foreign exchange services manually.”
A team of IT specialists and external cyber security experts “have been working continuously since New Year’s Eve to isolate and restore affected systems”.
Issuing an apology to customers, the company added: “We are doing all we can to restore our full services as soon as possible.”
Travelex describes itself as the world’s leading foreign exchange specialist and operates in more than 70 countries, including 1,200 branches and 1,000 ATMs.