Dr Gabriel Scally has said Ireland should have a full quarantine system that applies to everyone who wants to come in.
He was speaking as talks are due to take place later this week between officials and ministers on a proposal to extend the number of countries on the mandatory hotel quarantine list.
The discussions will focus on the capacity of the hotels, whether there are sufficient staff and the legality of extending the list to more European Union countries.
The Government added 26 countries and states to the list last week, but the US and EU states were not included.
Dr Scally, professor of Public Health at University of Bristol, told Newstalk Breakfast variants need to be kept out - regardless of where they are from.
"I think there is one over-riding principle, and that is to keep the country safe.
"That means not importing variants, and it doesn't really matter where they come from - they're just going to be as dangerous.
"The fact that it comes from the US or another EU country is neither here nor there from a public health point of view.
"And neither is it what passport someone has or what their country of travel is, because they could have picked up this variant anywhere around the world and they could bring it in by coming any route.
"On public health grounds, you really should have a full quarantine system that applies to everyone who wants to come in.
"And they should go through a managed isolation process - that's the fairest way of doing it, and it's also the safest way of doing it.
"You can't half-do quarantine measures".
Asked about why other EU countries are not imposing mandatory quarantine on each other, he said the push has come from Brussels.
"There has been quite a push from the European Commission to keep borders open, to avoid restrictions, not to have lockdowns - all of that sort of stuff.
"I can understand it from the European Commission's point of view: the European Commission doesn't really have any competency in health issues.
"What I mean is they don't have powers and responsibilities and so on.
"Responsibilities for public health are the responsibilities of individual countries, and they'll make up their mind.
"And there has been quite a bit of dispute between the European Commission and individual EU countries when they have put on controls - as indeed many of them have.
"Ireland's in a particularly good position from the point of view of dealing with COVID in that Ireland is an island and it's relatively simple to put in place measures for managed isolation".
'You can't get the balance right'
Asked by host Shane Coleman if Ireland would be getting the balance right, Prof Scally said there is no right balance.
"I think one of the things that's been learnt during this pandemic is you can't get the balance right between the economy and health: they go together.
"And the evidence is that countries that get the virus down to really low levels, and keep it there, they're the countries that are doing well economically.
"It's countries that have tried to live with the virus and have on-off lockdown situation - just like Ireland has had to do or the UK - those are the countries that have suffered economically.
"Economically, the best thing to do for the country is to get the virus down, keep it down and keep it out".