NPHET says higher-grade face masks may offer more protection to people at greater risk of getting Covid-19.
It says FFP2 masks should be considered by anyone who's a confirmed case, a household contact or visiting a vulnerable person.
But it's stopped short of recommending them to everyone ahead of cloth masks.
Paul Moynagh, Professor of Immunology at Maynooth University, says there's clear evidence they're a better option:
"Certainly, the evidence base is there to support their use.
"I don't really understand in terms of why it has taken so long, it seems to me we're coming to this very late.
"I think they would help, but they're not a panacea."