Irish Foreign Affairs Minister Simon Coveney has said the EU's botched plan to block vaccine exports into Northern Ireland has "created tension that we could have done without".
Mr Coveney blamed "some clever technician or lawyer" in the European Commission for the proposal to trigger Article 16 of the Northern Ireland protocol agreement that would have temporarily nullified the post-Brexit deal to ensure an open border on the island.
The move infuriated governments in Belfast, Dublin and London and prompted a series of phone calls between the Taoiseach Micheál Martin and European Commission President Ursula von der Leyen on Friday night, before the EU confirmed that it would not invoke Article 16.
Mr Martin told RTÉ last night that the protocol had become "collateral damage" and that "lessons have to be learned" from the debacle.
Mr Coveney said he had been assured that such a unilateral move would not happen again, describing what happened as "an unfortunate incident, it shouldn't have happened" and wouldn't have had the commission consulted with the Irish Government beforehand.
"This was not welcome, it created tension that we could have done without. Yes, it was fixed quickly and it's to the commission's credit that they did that - but this was a mistake that we need to learn some lessons from," he told the Sunday Independent.
He later added: "Let's not pretend that damage wasn't done in the meantime - it was - but we can work to address that I hope."
The EU is attempting to introduce a new export control mechanism designed to restrict shipments of Covid-19 vaccines out of the EU if the bloc's own orders are not being met.
It comes amid a furious row with vaccine-maker AstraZeneca, which has told the commission it cannot fulfil orders promised. Ireland expects around 300,000 fewer vaccines in the first quarter as a result, impacting the roll-out to over-70s.
Mr Coveney said he understood the logic for the decision and said there was a fear that vaccines could be exported into the UK through Northern Ireland "as a back door", but said the proposal to invoke Article 16 "came from someone who hadn't been involved in the protocol and the understanding of the politics of the protocol".
First Minister Arlene Foster said yesterday that the UK government must "recognise the unreasonable disruption UK citizens living in Northern Ireland are currently facing" and called on Johnson to act.
Deputy First Minister Michelle O'Neill described the decision as "unwise, ill-judged and totally unnecessary".
"The protocol exists as a stable and lasting solution to avoid a hard Border on the island, thereby enabling the smooth functioning of the all-island economy and safeguarding the Good Friday Agreement," she said.
A source for the Executive said: "The protocol was used for wrong purposes and parties on the island of Ireland and the Irish Government won't take it lightly. It has given unionism a credible reason and momentum to their campaign of opposition."
Health Minister Robin Swann was expected to speak with Health Secretary Matt Hancock about the issue.
Meanwhile, a leaked document from the Executive, seen by the Sunday Independent, shows a growing list of concerns.
The document outlines the impact on the viability of some businesses, issues for online orders, the horticulture sector and fishing at the end of the transition period.
It states that British companies that trade directly and indirectly through the Republic of Ireland and Northern Ireland "were not prepared for the additional process for trading after the end of the transition period", explaining that readiness for the end of the grace periods in April and July is a "key issue".
The transport of mixed loads in a single lorry is another "major issue" and affects smaller companies "who are not benefiting from the grace period for supermarkets".
Another issue affects farmers moving livestock from Great Britain to Northern Ireland as "some animals have effectively been stranded in Scotland and Northern Ireland farmers have currently no available solution".
The report also states that "further work is required" to address the "risk of additional burden on the fishing fleet" and reveals that both hedging and seeds companies are unable to sell to Northern Ireland "due to the presence of GB soil".