NPHET "strongly" recommends against the public buying and using antigen tests on themselves
However, the CMO did say antigen testing could potentially play a "very important role" in controlled and appropriate circumstances such as workplaces.
NPHET is "strongly" recommending against the public buying and using antigen tests on themselves, according to Chief Medical Officer Dr Tony Holohan.
NPHET raised concerns last week after some supermarkets began selling antigen tests, which are faster but less reliable than PCR tests.
On Friday, however, the Department of Enterprise, Trade and Employment put out a statement encouraging the use of antigen tests in the workplace.
In the statement, Tánaiste Leo Varadkar said: "We now have a Government endorsed report on antigen testing and I know many employers are using it already. I am encouraging more to do so.
"These tests should be used as an additional health and safety measure and not as a substitute for any other precautions."
Asked at this evening's NPHET briefing about Varadkar's comments, the CMO responded: "In controlled and appropriate circumstances antigen testing has a very important role to play potentially.
"The use of antigen tests by the general public, applying those tests to themselves... is still something we strongly recommend against.
"We're still clear on that. I know these tests are available. I know people are buying them. We still strongly recommend against that because you cannot rely on a negative result. In effect, a negative result does not tell you anything.
"We're concerned that people will take these tests, test themselves, get a negative result and conclude - and perhaps it might feel reasonable for them to conclude but it's wrong - that it's okay for them to go into somebody else's house, to a gathering, or to an event that maybe otherwise wouldn't be safe."
On the use of antigen tests in the workplace, Deputy CMO Dr Ronan Glynn stated the tests should only be used by employers together with other public health measures.
He explained: "The guidance today doesn't simply say 'we advise that you go and use antigen testing'.
"I think it says 'antigen testing can be considered as one more layer in a multi-layered range of approaches to protect your employees'."