NHS services in South Yorkshire are still recovering from a cyber attack which brought the health service to its knees last Friday.
Members of the public have been asked to 'remain patient' as GP practices and other NHS services in the area get back up to speed following the major assault on their computer systems.
Both Sheffield and Doncaster Clinical Commissioning Groups (CCG) said GP practices in the areas would be open as usual today but many were still bringing their IT and clinical systems back online.
But they said some GP practices would not yet have full access to patient records, prescriptions, appointment systems and in some cases telephone systems.
They have issued the following advice to patients:
* If you already have a GP appointment booked for Monday, this will go ahead. Please do not ring your surgery to check as they will be extremely busy and attend for your appointment as normal
* People who have GP appointments should turn up as normal unless they are contacted directly and told not to.
* If you need to book an urgent GP appointment on Monday morning, you will be able to do so but please bear with us if you have difficulty in getting through to your practice and keep trying
* Please bear in mind that practices may be running more slowly than usual if they are unable to access some of their systems and the public are asked to be patient with staff.
* All phone lines for GP practices are working. However, there is a possibility that practices that use electronic call queuing systems may be affected. In this instance patients may experience some delays in getting through. If this happens, keep trying to get through whilst NHS IT technicians work to resolve the problem.
The CCG said hospitals had continued to treat patients throughout the weekend and were 'working hard' to return to normal services.
But it said they were likely to remain very busy and urged people only to use A&E services and dial 999 if there is a genuine emergency.
Patients with planned hospital appointments are advised to attend as usual unless they are told otherwise.
The Wanna Decryptor or WannaCry virus has reportedly infected hundreds of thousands of machines across the globe since Friday.
The NHS was particularly badly hit, with hospitals in parts of the country forced to cancel treatments and appointments.
Sheffield Teaching Hospitals yesterday said it had not been affected by the cyber attack but had stopped external emails from coming into its hospitals as a precaution.
Doncaster and Bassetlaw Teaching Hospitals NHS Foundation Trust said it was also unaffected.