A spokesperson for Save Our Bingo has said there is concern that a bill that will reduce the amount of money paid out on a bingo win will force many bingo halls to close.
Deirdre Doherty told RTÉ's Morning Ireland that there are concerns the halls will not be viable to run.
She said she was unsure of the exact number of bingo halls but it "is a lot" and could be in the hundreds.
Ms Doherty said bingo is the only outlet for many people around the country for whom it is "the social event of the week".
She added that many of these people "don't drink, don't smoke or do anything else".
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Ms Doherty said she was unaware of any proposal that would ensure 25% of any money collected on the night would go to charity.
She said: "A lot of people down the country, and in Dublin, use this as their only outlet. They only go to bingo. They don't drink, they don't smoke, they don't do anything else.
"It's their social event of the week. It's basically about the social interaction."
A protest arranged by the Save our Bingo campaign group is under way outside Leinster House.
The group said it is made up of players from across Ireland who want to "save the game of bingo from being destroyed by the Government".
Minister of State David Stanton has responsibility for gambling policy and is currently steering the bill through the Oireachtas.
In a statement, Mr Stanton said he did not accept that bingo halls would be forced to close.
"This is a modest proposal. It will simply ensure that the charities receive a fair share from the bingo operators who act as their agent; that is a minimum of 25% of the proceeds of the bingo," he said.
"I don't accept that bingo halls would be forced to close as a result. It has always been the case under the 1956 Gaming and Lotteries Act that a bingo operator could act as an agent of a lottery licence holder but that licence holder must be a charitable or philanthropic cause. This is not changing."
The new law will see that payments in future will mean a maximum of 50% of the proceeds go to prizes; a maximum of 25% go to the charity, and a maximum of 25% go to expenses incurred in the operation of the lottery.
Mr Stanton's department said this "new payment matrix represents a progressive measure that ensures that charities receive a fair share from bingo operators and is both balanced and sustainable".
The Gaming and Lotteries (Amendment) Bill is going before the Dáil tomorrow.