Wirral University Teaching Hospital NHS Foundation Trust declared a 'major' cyber security incident on Monday 25 November, which affected Arrowe Park Hospital and Clatterbridge Hospital, which the Trust manages.
The hospitals had to cancel all outpatient appointments scheduled for that day as healthcare professionals no longer had access to records and results, as everything was done electronically and all systems were down.
In the most recent update issued by the Trust on Thursday 28 November, the Trust stated that it expects this issue to 'continue over the weekend'.
A Wirral University Teaching Hospital spokesperson said: "After detecting suspicious activity, as a precaution, we isolated our systems to ensure that the problem did not spread. This resulted in some IT systems being offline.
After detecting suspicious activity, as a precaution, we isolated our systems to ensure that the problem did not spread
"We have reverted to our business continuity processes and are using paper rather than digital in the areas affected. We are working closely with the national cyber security services and we are planning to return to normal services at the earliest opportunity.
"While services continue to be available, there has been disruption to planned services, for example, some scheduled appointments are affected. Unfortunately we have had to postpone some procedures which will be rescheduled. The public are advised to continue to attend any scheduled appointments, along with their appointment letters, unless contacted otherwise.
"The Trust continues to prioritise emergency treatment but there are likely to be longer than usual waiting times for unplanned treatment in our Emergency Department and assessment areas."