The HSE said on Twitter that the temporary shutdown was a “precaution”.
Leo Varadkar said the attack was “very serious” and could affect systems throughout the weekend and into next week.
Tanaiste Leo Varadkar has warned that the ransomware attack could affect services throughout the weekend and into next week (Niall Carson/PA)
He said: “It’s coming at a time when the health service is extremely busy doing lots of other things.
“It’s going to be a very difficult time for the health service.
“I spoke to the HSE this morning and also Eamon Ryan, the minister responsible for cyber security.