Businesses in Ireland have called on the Government to increase funding for cyber security protection following the massive hacking event that has spread around the world since Friday.

Family doctors have been warned not to use their practice computers tomorrow until they are certain their anti-virus security systems are up to date.

More than 200,000 computer systems in nearly 100 countries have been infected with the so-called WannaCry ransomware since Friday.

The software locks files or a whole machine until a ransom is paid.

The malware has caused severe disruption to health services, industry, transport, academia and law enforcement in many places around the world.

In Ireland, there has only been one reported infection in a system at a small voluntary healthcare facility in Wexford.

Its computers, which were not connected to the Health Service Executive network, have been isolated.

On Friday the HSE cut off its network from external communications as a precaution.

The precautionary decision by the HSE to keep its network quarantined from external connections means its facilities will be unable to receive emails from outside the organisation.

But HSE chief information officer, Richard Corbridge, said the impact on patients is unlikely to be significant because email is not often used to communicate with patients.

The ongoing process of checking that HSE systems and devices have security patches in place may, however, lead to some disruption to services tomorrow morning.

Every hospital has its own plan in place to communicate any potential problems to patients in advance, Mr Corbridge said.

The HSE is also contacting staff to inform them of what to do tomorrow morning to ensure the network remains ransomware free.

Outside of the health service, the Government's National Cyber Security Centre continues to co-ordinate the response across all government departments and agencies to the ongoing threat.

Business group Ibec has urged companies to exercise extra vigilance over the coming days.

It also called for extra resources to be allocated by the Government to ensure the State meets the cyber security threat head on.

Richard Browne, Director of the National Cyber Security Centre, told RTÉ News that the malware in question is very large and is spreading rapidly.

He said many people will have put in place contingency plans to deal with something like this and that many Government departments and agencies have been working through the weekend to make sure adequate anti-virus software is in place.

However, he said it was "early days" in establishing exactly what they are dealing with and the full extent of the attack may not be known until tomorrow morning.

Mr Browne advises that people should make sure their anti-virus software is up to date and that machines are backed up as often as possible.

He said it is inevitable that we will see more of these types of attacks and that the State has had a national cyber security plan in place since 2015.

As the nature of these incidents is constantly changing, forthcoming legislation on protecting critical national infrastructure will be vital.

What is ransomware?

Ransomware is malicious software which locks computer files and forces users to pay the attackers a designated sum in the virtual Bitcoin currency to regain access to the files.

Ransomware is used on PCs as well as tablets and smartphones.

How can you protect against ransomware?

There are several simple rules that can be followed to reduce the risks of a ransomware attack.

Among them are regularly updating the computer's security software which can correct any flaws exploited by the virus.

In case of a cyber attack, the authorities advise disconnecting the infected equipment immediately from the network, in order to isolate them.

In the case of a virus affecting a business or an institution, the IT experts should be alerted right away.

Authorities also recommend not paying the hackers the ransom demanded - because it is no guarantee that access to the data will be restored.

Read more from RTÉ's Science & Technology Correspondent: Ransomware - questions and answers