The work to rule action by more than 40,000 nurses has entered its third day today with no end to the dispute in sight.
Further disruption is expected to hospitals as nurses are not answering telephones, except in essential cases and are refusing to carry out clerical, IT or administrative work. They are also recording engagements with patients manually.
According to the Health Service Executive (HSE) A&E departments are experiencing backlogs, with outpatients in hospitals, community-based services, and psychiatric services also suffering service delays.
In a statement, the HSE said the industrial action would cause "significant disruption" and "hardship and distress to patients".
Yesterday the Irish Nurses' Organisation (INO) and the Psychiatric Nurses' Association (PNA) said they had plans to step up their action by walking off wards from next week.
At a press conference in Dublin the unions said they would announce on Monday a series of rolling work stoppages, with the first on Wednesday.
Speaking after a strategy meeting, INO general secretary Liam Doran said the unions had decided to wait until after Easter to carry out the rolling work stoppages so that it would not affect patients in hospital who were hoping to get out by the weekend.
He said the full details of the proposed stoppages have yet to be decided and would be announced on Monday.
PNA general secretary Des Kavanagh said his members were "absolutely resolute" and "in for the long haul".
They were prepared to carry on with the action as long as it took to get a resolution, he said.
The work-to-rule action, which started at 8am on Monday, is being taken by the unions as part of their campaign for improved pay and conditions, with increased pay and lower hours their chief goals.