Doctors in the country's largest hospital are having to work 24-hour shifts during the coronavirus crisis.
The gruelling shifts for junior doctors have been introduced at St James's Hospital in Dublin as it comes under pressure to care for the rise in patients who are seriously ill with the virus.
Hospitals are facing difficulties due to the number of staff who have had to self-isolate after contracting the virus.
A spokeswoman for the hospital said: "A healthcare crisis like Covid-19 demands a flexible response."
After consultation with junior doctor staff, and having reviewed contingencies around safe and sustainable rostering, St James's Hospital has introduced a 24-hour shift system for some non-consultant hospital doctors (NCHDs).
Longer shifts decrease the risk to patients and allow for more doctors to be available to look after Covid-19 patients.
"We are very grateful to our NCHDs for their hard work and dedication during this crisis," she said.
"They are key members of the multidisciplinary St James's team which is responding with extraordinary professionalism and commitment."
She said the system, and staffing generally within the hospital, is under daily review.
"The Organisation of Working Time Act allows for flexibility in rostering arrangements during emergency periods.
"The hospital's priority is to provide safe staffing levels to look after patients during this crisis."
Hospitals around the country are particularly worried about having enough staff skilled in caring for patients in intensive care or in beds where they are ventilated.
Nurses with comparable skills who had been working in operating theatres have received training in recent weeks in critical care as part of the preparations for the escalation in seriously ill patients.
Hospital consultants, including surgeons, are also being redeployed to areas such as emergency departments as part of the hospitals' overhaul to cope with the influx of coronavirus patients and also take care of patients who are hospitalised with non-Covid urgent conditions.
The HSE received around 70,000 applications from workers with health-related skills during its recent "Be on call for Ireland" recruitment drive. Job interviews have been under way among many retired nurses and doctors who have generously volunteered to return to work and relieve the pressure on colleagues.
Meanwhile, the Irish Nurses and Midwives Organisation (INMO) said the Government must act to provide childcare to frontline healthcare workers.
School and creche closures have left many healthcare workers unable to attend work due to childcare responsibilities.
The INMO is also aware that informal childcare networks of friends and family are becoming less viable, as many grandparents "cocoon".