Hospitals in Ireland suspected of being hit by the worldwide cyber attack had been targeted by a different, older virus, health chiefs have revealed.
The Health Service Executive (HSE) has delayed making a decision on lifting external email access for patients to the HSE network until Wednesday afternoon, amid concerns over the global ransomware cyber virus.
The Police Service of Northern Ireland's Cyber Crime Centre will continue to actively participate in the national co-ordinated response to this attack and we would encourage all local businesses and public services to take immediate steps to protect their systems and reduce their vulnerability. Internal emails had also been blocked, but were restored yesterday morning, and Mr Corbridge said it was unlikely that any of these interruptions would have a significant impact on patient care.
The news comes after the HSE chose to keep its network isolated from external communications for a further 48 hours as a protection against cyber attack.
The situation in Ireland is being monitored by the National Cyber Security Centre in the Department of Communications, Climate Action and Environment. The issues were not related to the ransomware cyber attack, and affected two administrative computers that did not hold patient records.
A spokeswoman said that due to the threat its inward email system had been frozen - which means it has not received any notifications of child protection concerns via email since Friday.
More than 200,000 institutions and organisations were infected by the "WannaCry" virus which struck in the United Kingdom and Spain first on Friday before spreading around the world.
In England, 48 NHS trusts fell victim, as did 13 NHS bodies in Scotland.
Businesses are on high alert this morning following fears a massive computer virus could spread to Ireland.
Meanwhile, Tusla, the Child and Family Agency, expressed concerns about children who may be at risk of abuse as a result of the email shut-down.
Elsewhere, the HSE said it opened six helpdesks and ran a communications campaign to advise staff about turning machines on and waiting for anti-virus upgrades before starting online work.
Richard Corbridge, HSE chief operations officer, yesterday confirmed the attempts to attack computer systems across the health service had been as "virulent" as in other countries.