Government bodies and other organisations could also be affected by the malware attack that brought down some NHS services, a cyber security expert has warned.
Companies operating large networks, thought to be particularly vulnerable, are being urged to make sure they are secure in the wake of the attack.
"Absolutely it's highly possible that as the days come forward unfortunately we are going to hear that more organisations and government bodies are going to have been affected," cyber security expert Paul Norris said.
"Unfortunately, it's going to be big names and it's going to be organisations that have got weakened security controls that are going to be mostly impacted by this."
The full scale of the global cyber attack that caused mass NHS disruption may only become apparent when people return to work on Monday.Read the full story ›
Hospitals across our region say they are getting back to normal after a massive cyber attack disabled their computers.Read the full story ›
The head of the UK's cyber-security agency says experts are "working round the clock" to restore NHS systems in the East.Read the full story ›
The Labour leader Jeremy Corbyn said warnings to renew cyber protection in the NHS were ignored.Read the full story ›
Colchester Hospital has warned patients will continue to face delays and cancelations to appointments because of the cyber attack.Read the full story ›
Appointments at the James Paget University Hopsital in Gorleston have been cancelled this weekend after it was hit by a large-scale cyber attack.
Around 40 hospitals nationally and 74 countries have reportedly been targeted.
James Paget has apologised for the inconvenience caused to patients and have tried to contact as many affected as possible.
For info - All appointments (clinic or surgical) booked for this weekend at JPUH are cancelled due to the IT issues we are experiencing
Kettering General hospital has taken the decision to close down all external IT systems following the NHS cyber attack.
The hospital issued a statement on it's website saying; "In order to maintain patient safety, confidentiality and he functioning of our systems across the county system leaders have taken the decision to close down all external IT systems, including email, websites etc.
"We would ask that patients do not attend A & E or other emergency services unless it is a real emergency."
The hospital says they are not planning to cancel scheduled appointments next week and apologised that systems will be slower than usual.
IT systems are down at up to 40 NHS trusts across England and Scotland.Read the full story ›
A number of hospitals in the Anglia region have confirmed they have been affected by a suspected cyber attack on the NHS.Read the full story ›