A veterinary company says it has suffered “significant operational disruption” following a cyber incident over the past week.

Veterinary giant CVS Group, which operates around 500 veterinary clinics around the world, said it had responded to limit the impact of the attack but that its UK operations had been particularly disrupted.

CVS said the incident involved “unauthorized external access” to a limited number of its IT systems.

In response, the company temporarily shut down its IT systems to prevent wider unauthorized access.

The company said the move successfully prevented the hackers from further accessing its systems but had a “considerable” impact on operations.

Professional third-party advisers are investigating the incident, which has also been reported to authorities including the Information Commissioner’s Office “due to the risk of malicious access to personal information”.

The company, which employs more than 9,000 people, said its UK operations had been particularly affected by the attack and its response.

“Through the efforts of our colleagues, we continue to provide a consistent high level of clinical care to our customers and patients across the majority of our operations,” CVS said.

“IT services for our practices and business functions are now safely restored in most areas; however, due to increased levels of security and monitoring, some systems are not working as efficiently as before, which may result in ongoing operational impacts.”

The London-listed company said it was accelerating plans to move its practice management system and related IT infrastructure to the cloud.

It said the incident, and the security response to the attack, “may have an impact on operations for weeks.”