The HSE is asking some hospitals to prioritise urgent treatment and COVID-19 care over the next two weeks due to pressure on the system.
Officials have also asked hospital managers to identify extra ICU capacity to deal with an expected rise in COVID-19 patients.
There are 611 people with the virus in hospital and 118 in intensive care - with just 17 adult ICU beds available nationwide.
Daily case numbers remain high, with the five-day moving average of new cases still over 4,200.
Speaking on Newstalk Breakfast, HSE CEO Paul Reid said hospitals are under severe strain.
He said: “If you look back to January, we had around 200 people in ICU - around 10% of our COVID patients.
"Now, around 20% of our COVID patients are in ICU - that’s a severe draw on our ICU capacity.”
Mr Reid said the HSE is using private hospitals to give extra capacity, and are currently working to increase their private hospital use to around 2,800-3,000 bed days per week.
Officials are also looking to see what surge capacity can be drawn upon to create extra ICU beds.
However, he said other "immediate and urgent" action is also needed.
He said: "Some of that does revolve around elective care, where we’ll have to prioritise urgent elective care.
“The reality is it has been taking place over the last number of weeks… hospitals would be making their own judgements and decisions.
"What’s really become quite precarious is the issue around our big hospitals… over the next 14 days, [they’ll] try to keep a primary focus on urgent care."
However, he said the extra capacity from private hospitals will give "some relief" amid the current surge.