As many as 5,000 HSE staff are currently out of work due to Covid-19, Ocean FM News has learned.
And there are fears this could worsen because of the highly transmissible Omicron virus.
The staffing situation is believed to have been one of the main reasons behind the new restrictions introduced earlier this week.
The absenteeism is also thought to be impacting other public services, such as the Prison Service and the Gardai.
Minister of State and Sligo Leitrim TD Frank Feighan says this is a major issue for a number of front line services.