The Cabinet has agreed to increase the self-isolation period for travellers from Britain from five to 10 days for those who are not fully vaccinated against Covid-19.
Those who are not fully vaccinated must take a second PCR test at the 10-day mark.
Minister for Health Stephen Donnelly on Tuesday night confirmed the measure, adding that the Government continues to advise against all non-essential international travel.
The tightening of travel restrictions between Britain and the State had been expected and has been prompted by growing concern over the rapid spread of the Delta variant there, which has led prime minister Boris Johnson to delay a planned reopening by four weeks.
Speaking before the Cabinet met, Minister for Transport Eamon Ryan said genome testing of Covid-19 cases in Ireland had shown “small numbers” of the variant, which originated in India, “more in the eastern half, than on the west” side of the country.
He said any tightening of travel restrictions between Britain and Ireland was expected to last for just a few weeks to stave back the spread of the Delta variant.
Mr Ryan said the tighter, temporary restrictions on people arriving into the State from the UK would allow time for the vaccine programme to progress, which would see the level of protection against the Delta variant improve.
“The more we can delay its spread, the better protection we have… it is being cautious,” Mr Ryan said.
It is also a legal requirement that people arriving from non-designated countries such as Britain, observe 14 days of home quarantine. This period can be shortened if a PCR test taken five days after arrival returns a negative result.
“Those who travel from Great Britain, who are not fully vaccinated are now requested to remain in quarantine and seek a further test at least 10 days after arrival in Ireland, in addition to the day five test,” the Department of Health said.
“This day 10 test is also free of charge. You can get this test by visiting any HSE testing centre...The HSE will shortly introduce a booking portal for the day 10 test as well.”
Mr Donnelly said variants of concern “continue to pose significant risks to public health and there is a specific concern around the Delta variant”.
The department said the HSE had also put enhanced contact tracing measures in place for all detected positive cases of Covid-19 with a travel history extending back 14 days and their close contacts.
One health expert has argued that a delay to the easing of Covid-19 restrictions here, similar to the one announced in Britain, would allow a “massive push” to double vaccinate people quickly and so counter fears of a surge in the Delta variant.
Dr Gerald Barry, assistant professor of virology at University College Dublin, said a large proportion of the population – including those who had one jab – remain particularly vulnerable to the more infectious strain.
“We are kind of on this tipping point now, where the Delta variant is potentially going to start causing problems in the country,” he said.
“It is still at very low numbers at the moment, we seem to be keeping tight control over it, but there is a worry if it starts to pick up it will cause us problems.”
Dr Barry said “there is no reason to doubt” the strain, which originated in India, would take off in Ireland as it has elsewhere, which could “cause a real problem” as more people start mixing in July.
“I would be very cautious opening up society too much for the simple reason that, although it might seem like we are in the situation where we have lots of protection across the country, we actually don’t,” he told RTÉ radio. “The percentage of the population that have two shots of the vaccine is relatively low.”
Data shows two jabs give “very good protection” against the Delta strain but one jab gives just 33 per cent effectiveness, leaving huge swathes of the population “still very vulnerable”, he said.
“There should be a massive push to double vaccinate people, particularly people in their 60s that are vulnerable and can be really badly affected by this variant.”