Foreign Affairs Minister Simon Coveney says a gathering in breach of COVID-19 guidelines at his department was 'a serious mistake'.
But he believes the consequences for those involved 'have been significant'.
He was speaking after a report found a 'serious breach' of guidelines at the gathering in June 2020.
Some 20 staff celebrated Ireland winning a seat on the United Nations Security Council, and alcohol was provided.
The former secretary-general of the department Niall Burgess has agreed to donate €2,000 to charity, while three other officials are donating €1,000 each.
They will face no further action.
Minister Coveney told Newstalk Breakfast the context is important.
"This was not an organised gathering, this was people working in the workplace.
"But after the result of the vote came through from New York, and Ireland was elected to the Security Council, people came together for a photograph in celebration for about a minute.
"This is very different to some of the accusations in London around organised parties and so on."
He says the posting of a photo on social media by then secretary-general Niall Burgess - now Ireland's ambassador to France - was a lack of judgement.
"It was an uncharacteristic mistake: I've known Niall Burgess for a long time, he's a very experienced and very able civil servant.
"I think what's very clear from this report as well is that the Department of Foreign Affairs was taking COVID guidelines and restrictions very seriously in terms of people working from home.
"And there was an awful lot of preparations from a COVID guidance perspective to allow people to come into work this day... in order to work on getting elected to the Security Council."
'This wasn't an organised party'
Miniter Coveney says he is not making excuses for the breach.
"This was a serious mistake that shouldn't have happened and I don't excuse it in any way.
"I'm just trying to put a context around what happened - this wasn't an organised party with people invited to it.
"This was a spontaneous celebration immediately after the vote that lasted for about a minute, involved about 20 people and that shouldn't have happened".
Asked if there should be more severe consensus, as suggested by Senator Gerard Craughwell, Minister Coveney says consequences have been significant.
"The leadership there was coming from the secretary-general at the time, and I think this report points to that failing.
"I think the consequences for the then secretary-general have been significant actually.
"There's been a lot of public commentary, a lot of media commentary of this issue, he's been asked to make a financial donation of €2,000.
"I think, from a reputational perspective and from a public focus, there's been a very serious consequence for what happened".
Asked if he wished this was handled differently, he says: "I would like that this event never happened in my department, but it did".
