People are being left in 'crazy scenarios' where they have to decide whether they can afford to have a child.
Sinn Féin spokesperson on Children Kathleen Funchion said they want the cost of childcare cut by two-thirds in the upcoming budget.
The party is bringing a Dáil motion on the issue later, urging the Government to provide additional funding to the sector.
Deputy Funchion told Newstalk Breakfast fees will become a bigger issue in the winter.
"We know that many families struggle to actually access childcare due to the fees, it's in the region of €800 to €1,300 per month - that's just for one child," she said.
"If you have more than one child, obliviously it's a lot more again.
"We also know that this has been an issue for several years, but particularly at the moment given [that] we're back into the winter months.
"People will be struggling with increased electricity and fuel and all of those other cost of living measures."
'Investment into the service'
Deputy Funchion said she believes there has never really been an attempt to drive fees down.
"There was a fee freeze last year, and a small amount of money went into that sector," she said.
"It wouldn't be done through a tax break; it would be done through investment into the service itself, into the providers.
"If you increase investment, and actually do it properly... that you would then ask providers to reduce their fees in line with getting this funding.
"It would be a kind of a contract-type situation."
Deputy Funchion said the proposal would cost around €267 million.
"We've actually been proposing this for the last number of budgets," she said.
"I actually find it really frustrating that we haven't seen Government make any moves.
"In our budget last year, the cost was around €267 million in additional funding.
"Later this week we'll be launching our budget submission for this year, the figures will be a little different obviously because there was a fee freeze last year".
'That's what people want'
Deputy Funchion said she doesn't believe cuts are necessary elsewhere to achieve a fee reduction.
"You can't do it all, but I'm specifically speaking about the childcare and the issues in that sector," she said.
"Later this week we're launching our budget submission which will contain exactly what we feel are priorities.
"That's a small flavour of it - health, housing, childcare - and that's kind of been our situation for the last number of years.
"I also really genuinely believe that's what people want.
"They want to be able to live their lives, not planning out 'Can we afford to have a child? Can we afford to have a second child?'
"They're the kind of crazy scenarios people are being left in," she added.
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