Taoiseach Micheál Martin says the Government is giving "very active consideration" to moving the country to level five restrictions.
NPHET has recommended moving the entire country to the highest level of restrictions for six weeks.
It's the second time in recent weeks that health officials have recommended a strict lockdown, amid continuing increases in coronavirus cases and associated hospitalisations.
Micheál Martin, Leo Varadkar and Eamon Ryan will meet tomorrow with the Finance Minister Paschal Donohoe, Public Expenditure Minister Michael McGrath and Health Minister Stephen Donnelly to discuss moving to level five restrictions.
Mr Martin - who is currently in Brussels for an EU summit - said the NPHET recommendation is being 'actively considered' by the Government.
NEW: The Taoiseach says they are giving moving to level five "very active consideration."
"The situation is very serious and we will need further action in relation to this. The government will give this very detailed consideration examining all aspects"
— Seán Defoe (@SeanDefoe) October 16, 2020
He said he 'doesn't want to put a timeline' on when a decision might be made on level five restrictions - saying it's a massive call and they want to consider all the detail of it first.
Tánaiste Leo Varadkar, meanwhile, said he wasn't surprised by the NPHET recommendation given the worsening situation with the virus.
Asked whether a lockdown could ensure a normal Christmas, Mr Varadkar said he would be "loath to make that kind of promise".
He noted it can take a lot longer to get out of lockdown than to enter it.
Level five would mean a return to strict restrictions for all people and businesses in the country.
It would be broadly similar to the lockdown earlier this year, with people urged to stay at home wherever possible and to stay within five kilometres of their home.
Only essential retail and services would be allowed stay open, while the likes of restaurants and bars would be limited to delivery and takeaway only.
However, schools would potentially remain open under the restrictions - with the Government insisting they are aiming to keep schools operating.
The NPHET recommendation came after two consecutive days of record new coronavirus numbers, with the 14-day incidence rate nationwide having now passed 200 per 100,000 population.