Pushing ahead with reopening the country now would mean a "significant danger" of making the same mistakes made last November, People Before Profit TD Paul Murphy has said.
He was speaking as Cabinet meets to discuss the next stage of reopening, with the return of indoor dining now expected to be delayed by at least two weeks.
It comes amid stark warnings from NPHET about the dangers posed by the Delta variant of coronavirus.
On Newstalk Breakfast, Deputy Murphy said he doesn't believe it's time to fully reopen restaurants and pubs, based on the NPHET data and information available publicly.
He said: "If we make a decision to reopen now, there’s a significant danger we’d be making the same mistake that was made at the end of November, which was absolutely disastrous.
“1,000 people died unnecessarily in January, and again in February. Obviously, we wouldn’t be at that scale, because we do have vaccination and some of the most vulnerable people are fully vaccinated.
"But you have to remember most people in the country are not fully vaccinated."
He also argued that the people most at risk from reopening indoor dining would be young hospitality workers, most of whom have not been vaccinated yet.
Deputy Murphy said there have been choices when it comes to reopening, and he believes the Government made the wrong one when they ruled out full mandatory quarantine for people arriving from the UK.
He said: "We called for mandatory hotel quarantine for travellers from England, Scotland and Wales to stop or slow the spread of the Delta variant.
“If we’d taken the action a month ago, we wouldn’t be here… you’d succeed in significantly slowing down the spread.”
Ireland must have a 'difficult conversation'
Meanwhile, Prof Sam McConkey - the head of international health and tropical medicine at RCSI - said Ireland now needs to have a 'difficult, grown-up and adult' conversation about living with the virus.
He said: “What I’m saying quite publicly is if we’re going to try to live with COVID, we have to come up with some acceptable level of deaths and morbidity we’re comfortable with.
“To make that sensible and contextualise it, we have to look at something like road accidents - where there are between 200 and 300 deaths on the roads per year.
"If [COVID mortality is] equivalent to road accidents - and this is getting near that - should we as a society not be moving forward, because we all use the roads?"
He said his own modelling projects there'd be around 200 to 500 deaths related to COVID-19 if the 'step-wise' reopening continues as planned.
He said he isn't surprised by NPHET's estimates, saying his "middle of the road" estimate isn't much different to their best-case (165 deaths) and worst-case (2,000 deaths) scenarios.
Fianna Fáil TD Marc MacSharry said he agrees an adult conversation is now needed - saying Ireland's shown "no ambition" in developing a plan for living with COVID-19.
He said: “We’ve gone the scenic route far too often - towards masks, antigen testing, cutting the time between AstraZeneca [doses], and indeed approving AstraZeneca and Janssen for young people.
“We’re exercising an irrational fear of indoor activities."
He said NPHET has a job to do, but it's the job of the Government and politicians to "distil" their advice in order to have a functioning society.
