ST. JOHN'S, N.L. -- Cybersecurity experts say they are worried about the extent of the damage to the IT infrastructure of Newfoundland and Labrador's health system following a likely cyberattack last weekend.

Health Minister John Haggie said Monday the health system's data centre has "two brains" and both of them were affected by an attack, which led to the cancellation of thousands of medical appointments.

David Shipley, CEO of New Brunswick-based Beauceron Security, said today in an interview the loss of data backups is concerning because the rebuilding process could take weeks or months to complete.

The province has refused to release details about the alleged attack, but Shipley says it appears the likeliest explanation is that hackers infiltrated the IT network and are demanding payment in return for access, which is known as a ransomware attack.

Dalhousie University computer science Prof. Nur Zincir-Heywood said today in an interview ransomware attack programs can sometimes "stay in and eavesdrop for weeks and months," adding that they can spread into backup data storage.

Zincir-Heywood says it could be a time-consuming task to find the most recent uninfected backup, depending on how Newfoundland and Labrador's system is set up.