A respiratory physician says there should be no question of pubs and restaurants allowing smoking outdoors this summer.
Professor Luke Clancy says there should be no return to smoking areas outside.
The director-general of the TobaccoFree Research Institute told Newstalk Breakfast more people have died from smoking-related diseases than COVID-19.
"It's amazing to me: we watched this pandemic and we see the terrible mortality - so far maybe 4,000 people.
"During that time, at least 7,000 people have died from smoking-relating diseases, something that's entirely preventable.
"We're restricting freedoms to protect against COVID, which is only partly effective - this could be really effective and is really effective - and is causing greater mortality, and yet there seems to be some sort of resistance to bring it in.
"I cannot believe that NPHET do not say, or mandate, that they don't have smoking in outside areas."
He said even the indoor smoking ban had unintended consequences.
"We should never go back to having smoking areas outside.
"If you remember, when smoke-free came in, there was kind of a compromise.
"It was thought that 'Well there's some people who just cannot manage without a cigarette - and if they go outside and there's no food and there's no serving of them and they just have an area. And OK, there's no safe-level of second-hand smoke but they need somewhere' and this was allowed.
"But then it became something quite different: people went out with their friends, non-smokers went out to their friends and were exposed.
"And the facts are still that there is no safe level, and there are definitely increased levels in these areas.
"The idea that you would do this where there was food - I can't believe it - and I can't understand that this isn't a direction from NPHET.
"Public health would demand that there must not be smoking where there's food, and where there are other people and where there are non-smokers who could and will be damaged by it".
Prof Clancy said while he assumes smoking where food is served is not allowed, it still happens.
"I assumed that when the pubs opened again, that they'd be so glad to open that there'd be no question of them allowing people to smoke in the outside areas.
"But you can see on the pavements and so on people are smoking and seem to be indifferent to the needs of others.
"We have a lot of research now, when it came in we didn't know as much, but we now know that the levels outside are not negligible and they do cause damage".
'Why bother having NPHET?'
Smokers' rights group Forest Ireland says while smokers should be considerate to those around them, further regulations are not needed.
The group claims pubs and bars must be allowed to choose their own smoking policy in outdoor areas.
Spokesperson John Mallon says: "There is no justification for banning smoking in outdoor spaces. Smoking in the open air poses no health risk to anyone other than the smoker.
"Coming out of the pandemic the last thing the hospitality industry needs is the threat of smoking being prohibited outside pubs, cafes and bars.
"Tobacco is a legal product and smokers have a right to light up in outdoor spaces without restrictions designed to force them to quit.
"The war on smoking has become a war on ordinary people who just want to be left alone to live their lives as they choose without excessive Government intervention."
To this, Prof Clancy said: "I think that the time that we take our public health advice from Forest should be long gone.
"Why bother having NPHET or health committees or specialists when we could get our information from Forest?
"They have never agreed to anything that has curtailed smoking, even though their own members are dying of it".
Environment Minister Eamon Ryan has previously said any outdoor smoking ban would be difficult to enforce.
He said an outright ban is not workable.
"It wouldn't be proper or right if someone's at a table nearby if you are smoking.
"You might have to leave the table [and] walk to an area where you're not blowing smoke on to neighbouring tables.
"I don't think we can have a complete restriction on people from smoking outdoors.
"But where people are close to each other enjoying a dinner, I think the etiquette should be that you don't smoke", he said.