An expert in older people's health says taking vitamin D will help protect against COVID-19.
The Government has asked NPHET to examine the use of vitamin D in the fight against the virus.
Tánaiste Leo Varadkar said the Dáil on Thursday that he hopes the National Public Health Emergency Team will issue formal advice to be given to the public.
Quoting several sources of research, he added: "The respected Lancet medical journal says that it's uncontroversial to promote it, and there is a chance that it may be beneficial in terms of COVID-19 outcomes.
"Government has asked the NPHET to examine this, and to provide us with formal advice which we can then stand over and give to the general public."
It comes as more than 2.5 million vulnerable people in England will be offered free supplements.
Professor of Medical Gerontology at St James's Hospital in Dublin, Rose Anne Kenny, said there is clear evidence the vitamin is beneficial.
Speaking on Newstalk Breakfast with Susan Keogh, she said Ireland should be following the UK in offering vitamin D.
She commended Mr Varadkar for speaking out about the issue, and said the public health advice should include vitamin D as well as other guidelines currently in place.
She said: "Vitamin D should be part of 'wear your mask, keep a social distance, wash your hands, and take vitamin D supplements.
"The evidence for it is as good as washing hands at this point in time.
"in Ireland, because of our latitude, we can't get enough vitamin D from our food or from sunshine, so supplements are really necessary for everyone in winter.
"The level we're recommending, because of COVID, the level which benefits immunity is higher than the level recoemmended for bone and muscle health.
"That's why we're pushing this, it's higher than previous recommendations."
Professor Kenny says adults should take "a minimum of 800 international units a day" so that the blood level can get high enough to enhance immunity against the virus.