Transport Minister Eamon Ryan attended a large party organised by a Green Party councillor in the wake of the Dublin Bay South by-election despite health chiefs urging people to keep social circles small in outdoor settings.
The event, held at Merrion Cricket Club, was organised by Green candidate Claire Byrne, on July 29.
Prior to that, deputy chief medical officer Ronan Glynn had urged the public to avoid large gatherings and to only mix in small numbers outdoors.
Ms Byrne said the event was held "to thank those who campaigned” for her in the by-election, adding that “health regulations allow for up to 200 people to attend an outdoor event".
Details of the Green Party event were revealed as former children’s minister Katherine Zappone confirmed she would not take up a special envoy role with the UN after the process of appointing her was mired in controversy.
The role was never advertised, leading to claims it amounted to political cronyism by Fine Gael.
It has also been revealed Ms Zappone organised a private outdoor function at the Merrion Hotel in Dublin, attended by Tánaiste Leo Varadkar, six days before she was appointed to the €15,000-a-year job.
Turning down the role on Wednesday, she said: "It is clear that criticism of the appointment process has impacted the legitimacy of the role itself."
The invite to the Green Party event, seen by the Irish Examiner, was sent to 3,500 members who were encouraged to "share in your local groups".
Photographs from the event show Ms Byrne with a number of guests, with many people out of their seats.
Ms Byrne said "no more than 50 people were in attendance at any one time".
A spokesperson for Eamon Ryan said: “Minister Ryan attended an outdoor event at a sports club last week to thank those who campaigned in the recent by-election.
"The health regulations allow for outdoor gatherings involving up to 200 people for a variety of reasons including social and community purposes.”
Under current Fáilte Ireland guidelines, organised events, whether indoor or outdoor, are not permitted unless they are weddings or “non-social meetings, training and educational programmes considered essential to the operation of a business".
Ms Zappone also defended hosting the private function for friends and former colleagues and said prior to organising the event, she had enquired, and was assured by the Merrion Hotel, that it was in compliance with guidelines.
It is understood senior Government adviser Donal Geoghegan, the secretary-general of the Department of Children Fergal Lynch, and senior civil servants were among those who attended Ms Zappone's event.
Newly-elected Labour TD Ivana Bacik was also in attendance.
Another person who attended the event said: "It was billed as a thank-you event that she didn't get to have last summer for obvious reasons because we were in lockdown. She made some remarks at it and it was very much in that tone."