The HSE has taken measures to protect its I.T. network amid a major cyber attack which is affecting up to 100 countries around the world.
The "Wannacry" ransomware locks files and then demands payment to release them.
Britain's National Health Service, along with major companies in Spain, the US and Russia are coming under attack.
Gardaí say there are no reports of any Irish victims.
As a precautionary measure, the HSE has cut its networks off from external use.
Conor Flynn from Information Security Assurance Services - says its a wise move: