Counties where so-called "wet pubs" reopened at the end of September experienced an increase in the 14-day incidence rate of Covid-19 ten days later.
A data analysis survey carried out by Ernst & Young (EY) and provided to Government stated that this increase was not seen to the same extent in Dublin, where wet pubs were not permitted to reopen.
The report noted, however, that the reopening of pubs on 21 September - everywhere except the capital - also coincided with the opening of universities and specific sporting events.
Minister for Health Stephen Donnelly told RTÉ's This Week the evidence is "unambiguous" relating to wet pubs and that they can lead to "superspreader events".
He said gastropubs and restaurants are opening up with restrictions in place and he wants to see those complied with.
Speaking on the same programme, Professor Tomás Ryan from the school of immunology in Trinity College warned that "we may not see wet pubs reopening until there is a vaccine".
He said he thinks it is the wrong decision to ease restrictions for December and "against what is public opinion".
It comes after the EY report said that the 14-day disease incidence rate of Covid-19 started to increase in every county 10 days after pubs reopened.
But the rise in Dublin's incidence rate was lower than elsewhere. EY's analysis found that the growth in infections in the capital was 33% lower in October than the national average and 79% to 82% lower than counties with larger cities.
The EY report found that infection rates in Cork, Galway and Limerick jumped to three times the national average between 1 to 16 October.
"Not opening the wet pubs does appear to have helped Dublin with the subsequent increase in cases being slower than the national average," it stated.
Covid-19 cases in Cork city rose after wet pubs reopened on 21 September and also rose in the county area shortly after, the study stated.
There were also a number of GAA games in early October in Cork, which coincided with the virus rate increases. No matches occurred after this and cases throughout Cork began to fall 10 days later.
EY also reported that cases in Dublin took longer to decline after Level 3, indicating Level 5 was needed in the capital to control cases.
Last Friday, Micheál Martin confirmed that wet pubs would remain closed when Ireland moves to Level 3 restrictions from Tuesday, 1 December.
The Vintners' Federation of Ireland, which represents pubs outside Dublin, described the decision as a "stunning act of hypocrisy that has resulted in publicans being treated as second class citizens within the hospitality industry".
