Staff at the Department of Foreign Affairs were said to have "let down their guard" with celebrations in June 2020 while Ireland was under restrictions due to the Covid-19 pandemic.
Following reports of a breach of Covid restrictions, the department confirmed "lessons have been learned" since the celebrations after Ireland secured its place on the United Nations Security Council.
A photo showing a number of officials from the department's UN Security Council campaign team huddled together while posing for the image was published across a number of outlets on Wednesday.
According to the Irish Examiner, the photo was a selfie taken by then-secretary general of the department, Niall Burgess.
Mr Burgess, who has since been appointed as ambassador to France, tweeted the image with the caption: "Now we're walking on air." The tweet was reportedly deleted a short time later.
A spokesperson for the department said the team had been "working in a large open plan area of Iveagh House" throughout the day [June 17th, 2020] adding that "had Ireland not won the Council seat on the first round of voting, the team would have had to work through the night to campaign for a second vote the next day".
"As it happened, we won in the first round and in a moment of happiness, as the result came in, we briefly let our guard down by celebrating together," the spokesperson said.
"It was 18 months ago and steps have been taken to ensure lessons have been learned."
At the time of the incident the country was at Phase Two of the reopening plan when a person could only meet people from up to six other households and working from home was advised.