Pavee Point says it is 'shocked' and 'angered' after images of a large funeral in Leitrim began circulating.
The funeral in Carrick-on-Shannon for a member of a Traveller community saw over 200 people attend the burial at a local cemetery.
The Irish Times reports a marquee was erected in the area for mourners.
Gardaí are investigating 'a number of breaches' of public health rules, although say there's no investigation regarding the church element of the funeral.
They say over 80 fixed penalty notices have been issued as part of their operation.
Two arrests were also made on Wednesday under the public order act, in advance of the funeral.
Martin Collins from Pavee Point said the gathering at the cemetery is not acceptable in the middle of a global pandemic.
He said: "[My response] is one of shock, huge concern and indeed of huge anger.
"It's a highly contagious, deadly virus - people need to be a lot more responsible, and observe the public health guidelines.
"My message and the message of Pavee Point has been very consistent and clear to Travellers: please avoid large gatherings. It's not acceptable at this time."
He says he knows people will want to show their respects to the deceased and the bereaved family.
However, he says there will be other opportunities - and people will have the opportunity to visit the grave when restrictions are eased.
Mr Collins said he hopes people won't use the incident as a 'stick to beat Travellers with', noting that the vast majority of Travellers are observing the guidelines.
