Gardai entered a church after a large crowd gathered for Mass in Co Westmeath over the weekend.
The incident happened in the Athlone area of the county on Sunday.
Officers said they spoke to all those present and that they "complied with direction from Gardai".
However locals responded with fury to the scenes, with Pat from Co Roscommon saying that he was "outraged" by what he saw.
He told radio station Midlands 103: "The priest came over to me and asked me to calm the situation down, so out of respect for him I left the church.
"I was outraged when I saw it, I never thought I'd see something like that, this is like something from penal times."
In a statement, gardai reminded members of the public that the current Covid-19 restrictions prohibit large gatherings, with few essential exceptions.
A garda spokesman said: "Gardaí attended the scene of an event that took place on Sunday 18th April, 2021 at Athlone, Co. Westmeath at 10.15am.
"Gardaí engaged with those present and all persons complied with direction from Gardaí.
"The Health Act 1947 (Section 31A-Temporary Restrictions) (Covid-19) (No.10) Regulations 2021, as amended, are currently in force.
"In supporting the COVID-19 public health guidelines and regulations, An Garda Síochána has and will continue to adopt, a graduated policing response based on its tradition of policing by consent. This has seen Gardaí engage, explain, encourage and, as a last resort, enforce.
"Where Gardaí identify potential breaches of the public health regulations a file is prepared for the DPP in each case or a Fixed Payment Notice is issued where appropriate.
"The COVID-19 Pandemic remains a public health crisis and An Garda Síochána continues to appeal to all citizens to demonstrate personal and social responsibility to comply with Public Health Guidelines and Regulations in order to continue to save lives."
