The HSE says it’s unable to reassure people that their sensitive medical information won’t be leaked online.
Many appointments have been cancelled today following the cyber-attack on the HSE.
Doctors have been asked only to request blood tests in urgent circumstances.
It’s been described as a zero-day attack meaning it hasn’t been seen before.
Chief Operations Officer with the HSE, Anne O’Connor, says she can’t reassure people their data won’t be published by the hackers.
"I'm not able to reassure them.
"We're currently trying to dvertimne what data has been impacted by this.
"We've no evidence that anything is up on the web or has been stolen, but as I said that is being worked through today and over the coming days."
