Ryanair CEO Michael O'Leary has called for countries such as UK and Germany to be added to the travel green list.
He suggested the current list has 'failed' and now needs to be opened up to other European countries.
Currently, there are ten European countries on the list - meaning people arriving in Ireland from those ten places do not need to self-isolate for 14 days.
However, Mr O'Leary told The Hard Shoulder that Ireland's approach is still out of line with the rest of Europe.
He said: “We want to see [the Government] carry out what they said they would do when they first published the green list - they said they would add countries to the green list whose COVID case rate is lower than Ireland.
“Today the UK’s COVID case rate and Germany’s [rate] is lower than Ireland - and we’re calling for them to be immediately added.
"It’s going to be vital, especially as we move into September and business travel needs to restart.”
He said Ryanair has been flying without restrictions in most EU countries since early July, but Ireland has “remained closed to business” with the 14-day quarantine for new arrivals from most countries.
Mr O'Leary said he fully accepts that NPHET is made up of leading scientific experts, but that leading scientists in other European countries have allowed EU travel to resume for over a month now.
The Ryanair CEO said: “The question we keep asking - and which I say the politicians have failed to answer - is why is the science difference in Ireland than it is for every other EU country?”
He pointed to Ireland having only 14 COVID-19 patients in hospitals as of yesterday.
He said: “What ever happened to this flattening the curve? NPHET now seems to be stumbling into some zero-COVID policy that we’re not able to achieve.”
In terms of Ryanair’s own operations, Mr O’Leary claimed that almost all cash refunds due to customers "have now been cleared" - and that a refund is “on its way” for customers who haven’t received theirs yet.
He also said he believes a vaccine will be found for COVID-19, and that the airline industry will “rebound” once that is the case - suggesting travel is already recovering in countries such as Italy.
Mr O'Leary said he also believes the resignation of Fáilte Ireland chairman - and current Ryanair director - Michael Cawley is a "huge loss to Ireland", but that it was "his choice and he did the honourable thing".