Clare County Council has asked people "to act responsibly" this Bank Holiday after large crowds gathered in Kilkee over the weekend.
Images and videos on social media show dozens of young people cramped together at an event which locals say continued until after 3am on Sunday.
Gardaí made several public order arrests in the seaside resort on Saturday night after people attended a party in the town.
The council sought to remind people "that the coronavirus pandemic has not gone away and that it is vital we all continue to adhere to physical distancing and other public health guidelines".
Does the rules apply to some and not others? Absolutely disgraceful to see the scenes in #kilkee beach tonight and this isnt the first of it. Its no wonder cases are on the rise again with this nonsense going on and it isnt just at night either . pic.twitter.com/TUKgy960Jr
— laura fennell (@laurafennell2) August 2, 2020
Chief Executive of Clare County Council, Pat Dowling, said: "Young people must remember that anyone can contract the virus.
"Furthermore, anyone not adhering to the guidelines risks transmitting the virus to more vulnerable members of their families and communities, for whom the consequences may be dire.
"There must be no repeat occurrence of the scenes shown on social media, in Kilkee or anywhere else in County Clare.
Councillor Cillian Murphy told Clare FM that he has never seen anything like it in 30 years living in Kilkee.
Mr Murphy said: "All of this behaviour would be unacceptable at the best of times but it really is truly shocking now in the light of the COVID-19 pandemic.
"And I guess it's no surprise when we see images like we saw last night why we are seeing the majority of are in this under-25 age group."
If you are in Kilkee, the parents of a teenager and didn’t know where they were last night, then this post is for you. pic.twitter.com/j80IHXilFJ
— Cllr. Cillian Murphy (@Tri2bResponsibl) August 2, 2020
He wrote on social media yesterday that he had been helping to pick up litter and smashed glass and tidying vandalized shelters after the event.
Mr Murphy added that the aftermath of the gathering "really had to be seen to be believed".
He described the videos from the party and the behaviour on display as "truly shocking".
