The hackers targeted pathology services provider Synnovis.
More than 800 planned operations and 700 outpatient appointments were rearranged in the first week after the attack.
Primary care appointments are going ahead as normal, but blood tests are being prioritised for urgent cases.
Medical director Dr Chris Streather warned the disruption would be felt “for some time” and staff are “working round the clock” to mitigate the impact.
