Footage emerged on Saturday evening of what appeared to be a brunch event at Berlin D2 on Dame Lane, with no evident social distancing enforced.
A person can also be seen in the video standing on the bar pouring drink from a bottle into several people's mouths.
Chief executive of the Licensed Vintners' Association, Donal O' Keefe, said the incident was very damaging to the hospitality sector.
"I'm absolutely fuming, it's disgraceful behaviour," he said.
"The business in question does not hold a pub licence. We hope the gardaí investigate thoroughly and the full force of the law is brought to bear.
"It is simply not acceptable and it reinforces the need for gardaí inspections of all hospitality businesses because this kind of behaviour in a public health crisis is simply not acceptable," he said.
Restaurateur Jay Bourke, who is involved with Berlin D2, told RTÉ News that he was "absolutely mortified" at the video but believed it showed "20 seconds of madness".
Minister for Higher Education Simon Harris said the footage was "shameful".
A right kick in the gut & middle finger to everyone in our country who has worked so hard & sacrificed so much, to everyone who has lost a loved one or been sick with #Covid19, to every frontline worker and to every responsible business owner who have suffered so much. Shameful https://t.co/g16bwoEn16
— Simon Harris TD (@SimonHarrisTD) August 16, 2020
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"A right kick in the gut & middle finger to everyone in our country who has worked so hard & sacrificed so much, to everyone who has lost a loved one or been sick with #Covid19, to every frontline worker and to every responsible business owner who have suffered so much," he wrote on Twitter on Sunday morning.
Minister for Health Stephen Donnelly said most Irish people had sacrificed a huge amount to help suppress the virus. “They’ve shown huge solidarity. People are rightly sickened by these scenes. The reckless actions of a small few can have huge repercussions on everyone else,” he wrote on Twitter.
The vast majority of Irish people have sacrificed a huge amount to help suppress this virus. They’ve shown huge solidarity. People are rightly sickened by these scenes. The reckless actions of a small few can have huge repercussions on everyone else. https://t.co/BNQsjDk3m8
Advertisement— Stephen Donnelly (@DonnellyStephen) August 16, 2020
In a statement, An Garda Síochána said they do not comment on individual incidents involving suspected breaches of the public health regulations.
A spokesperson added: "Where potential breaches of the Public Health Regulations are identified and where a person does not come into compliance with the regulations, a file is submitted to the Director of Public Prosecutions for a direction as to how to proceed."
