Ryanair group chief executive Michael O'Leary has called for the removal of "ineffective quarantine measures" and said that by wearing facemasks Irish people can safely "go back flying" from July.
Mr O'Leary said that imposing a quarantine from tomorrow at airports and ports is "simply political game-playing".
He added that Ireland is emerging much more slowly from the health crisis than other European countries.
From tomorrow, people arriving in Ireland from any other country will, by law, have to fill in a form called the Covid-19 Passenger Locator Form, saying where they can be contacted.
They will also be asked to self-isolate for 14 days.
Chief Medical Officer Tony Holohan said the Department of Health "expects to have not only the airlines but the airport authorities helping them with the implementation of these measures".
He said the intention of the new locator form was to "provide a means through which we can follow up with passengers and people coming through the airports" to see if they were adhering to the advice about self-isolation.
He said they're also looking at what might happen by way of further measures in relation to quarantine.
Earlier today, Minister for Health Simon Harris says making it mandatory to self-isolate is "tricky, legally".
Speaking on RTÉ's Morning Ireland, Mr O'Leary said that Ryanair will be flying from 1 July to Spain, Italy and other European destinations.
The airline's decision is based on advice from the European Centre for Disease Control and the European Safety Agency, who support the resumption of airline business with the use of facemasks, he stated.
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He praised the work done by Government and health authorities in suppressing the virus in Ireland but said "advisers advise and politicians decide and it is time to decide and to get the economy going".
The Ryanair CEO said that Irish families are booking well-earned holidays in European locations at a time when Ireland is introducing regressive measures.
Mr O'Leary said that Ireland is planning to quarantine those returning from countries with a lower R rate of transmission of the virus and ask them to stay at home for 14 days.
He said scientific experts from ECDC and ESA have allowed travel to resume again once cabin crew, passengers and those at airports wear facemasks.
Mr O'Leary claimed the quarantine measures have "no basis in health measures and no basis in science", adding that people can fly "in perfect safety fully supported by the ECDC and the European Safety Agency".
Responding to Mr O'Leary's comments, Chief Clinical Officer of the Health Service Executive Colm Henry said he did not accept that the principle of quarantining is ineffective and that it has been introduced in many European countries, the US and Canada.
He warned that we should take great care before we "jump in and reverse" significant gains and the HSE is advising people not to fly for non essential travel.
HSE Chief Clinical Officer Dr Colm Henry advises against flying at this point in time, and says great care must be taken so that any gains made against the virus are not lost pic.twitter.com/CFFOkqXqJw— RTÉ News (@rtenews) May 27, 2020
Mr Harris also continued to urge people to avoid all non-essential travel from Ireland, saying that is what the country's doctors are telling us in the interests of our health.
The public health advice is to avoid all non essential travel off the island currently @morningireland - that's what our doctors are telling us in the interests of our health— Simon Harris TD (@SimonHarrisTD) May 27, 2020
Public health expert Dr Gabriel Scally, speaking on RTÉ's Today with Sarah McInerney, cautioned against unneccessary travel, saying the last thing Ireland wants to do is start importing new Covid cases from elsewhere.
He said it is a real danger and pointed out that there were a significant number of cases among Chinese people returning home, once restrictions there were lifted.
Dr Scally said there will be a lot of Irish people who want to come home soon and there is a risk they could bring coronavirus cases from other jurisdictions.
Speaking on the same programme, Kingston Mills, Professor of Experimental Immunology at Trinity College Dublin, said that quarantine measures should be in place for travellers coming from countries which are experiencing a high level of virus.
He said in countries like Brazil and the US "it is taking longer" to suppress the virus, so quarantine measures must be in place to ensure that Ireland does not "reimport" Covid-19.
He said if countries are "in a similar situation" as Ireland in terms of virus level, then "there is no need for quarantine between those countries".
Meanwhile, on the question of Ryanair refunds, Mr O'Leary said of €1.2 billion owed, €400m has been refunded.
He said the company is working through its liabilities in refunds and vouchers and by offering changed flights, but cautioned that it could take three to six months "to complete the job".
He also said we could readily reduce social distancing guidelines from two metres to one metre with more use of facemasks.
Ryanair is operating less than 1% of its normal flight schedules during April, May and June, while it plans to operate 40% of its normal schedules from 1 July.
The Ryanair boss also said that he expects Britain to join European nations in dropping Covid-19 quarantine plans in the coming weeks, as he noted a "big surge" in holiday bookings from the UK.
Last week Britain announced a 14-day quarantine from 8 June for arrivals from abroad, excluding the Republic of Ireland.
Mr O'Leary, who has described the plan as "unenforceable", said many customers in Britain appeared to be ignoring the rules, with booking rates in recent days showing the airline's 1,000 daily flights were likely to be more than half-full in July.