Rob Whiteman, CIPFA chief executive said: "The NHS ransomware attack needs to be a stark reminder for all government organisations to ensure IT security is optimal, regularly reviewed and upgraded, and given the resources to match our reliance on digital systems".
Patients are no longer being diverted away from accident and emergency units following the cyber attack, NHS England says.
A poll on Monday found three-quarters of Britons thought the NHS was in a bad condition and more than 50% blamed the Conservatives for its current woes.
It follows the "ransomware" cyber-attack which left NHS trusts across the United Kingdom without access to IT facilities and patients records.
People with diabetes who have blood tests or other appointments with their GP are urged to attend unless they are contacted by their surgery and told otherwise.
Services are returning to normal, but some places are still having problems.
The indiscriminate attack began Friday and struck banks, hospitals and government agencies around the world, exploiting known vulnerabilities in older Microsoft computer operating systems.
At Broomfield Hospital, part of Mid Essex Hospital Services NHS Trust (Midlands & East), trauma patients are being diverted to Southend University Hospital.
In his first public comments since the attack on Friday, Mr Hunt told Sky News: "I have this morning been briefed by GCHQ and the National Cyber Security Centre, and according to our latest intelligence, we have not seen a second wave of attacks and the level of criminal activity is at the lower end of the range that we had anticipated, and so I think that is encouraging".
'There have also been other reports made to our online cyber security network and the difficulty is of course there are literally hundres of instances of ransomware in Australia each week and so we are now seeking to confirm whether these are examples of the particular ransomware that has cause so much havoc for example in the United Kingdom'.
"If your business has been infected you should isolate the affected computer from your network to prevent the software spreading and use backup data to restore information'".
The home secretary said most NHS systems were back to normal after the cyber attack that left the service crippled.
More than 75,000 similar attacks reportedly happened in nearly 100 countries, with Russia, Ukraine and Taiwan hardest hit, according to the cybersecurity firm Avast. "This guidance was also reissued on Friday following the emergence of this issue".