The head of the HSE's test and trace programme says all available capacity is being utilised to deal with the huge volumes presenting for a COVID-19 test.
Demand for testing has surged as children returned to school in recent weeks – with 55,000 tests carried out in the past week alone.
A new record of 23,000 community tests was set on Monday. But that increased to almost 30,000 when hospitals and serial tests were added.
Niamh O'Beirne says schoolchildren are making up the majority of those presenting for a test.
She says the system is now at maximum capacity.
"We'll continue throughout the day to monitor the capacity, and to plan to allow as much possible testing take place.
"But we do know that our stage of capacity is 20,000, and in the last week we've already exceeded that four days.
"So we do expect testing to continue to be busy in the coming weeks, and we'll do our best to manage as much capacity as we can."
And she says antigen testing for close contacts could be introduced to help deal with "huge volumes" of people coming forward.
"We have deployed our maximum capacity at this point, so we will look again at the introduction of antigen testing for close contacts and we'd look again at overall our testing methods of self-referral and GP referral".
It comes as the HSE said there are currently no plans to scale back the State coronavirus testing programmes.
NPHET is currently considering a paper which calls for a gradual reduction in testing as Ireland moves to a new stage of its pandemic response.
But Maynooth Immunology Professor Paul Moynagh noted that we still have not experienced Delta in wintertime and warned against scaling back too early.
He told The Hard Shoulder: "I think we probably have to be careful in terms of when this is introduced.
"The reason I say that is because, in my view, there is still some uncertainty and risks with respect to things we are not so sure about.
"These include, for example, we haven’t really experienced Delta in terms of winter yet and we haven’t experienced Delta in terms of schools; when schools have been opened.
"Then thirdly and potentially more worryingly, breakthrough infections."