Unregulated childminders are offering to look after youngsters for as little as €10 a day - a move that is putting qualified professionals "under serious pressure to compete".
Online adverts seen by the Irish Independent show how under-pressure parents can leave their child with an unregistered adult from as early as 7.30am until 6pm for just €10.
Other adverts posted to social media outlets offer services for babies as young as six months old - for little more than the price of a packet of cigarettes.
Bernadette Orbinski Burke, chief executive of Child-minding Ireland, said fully tax-compliant child-minding businesses were finding it "virtually impossible" to compete with the "black market" trade.
She has also received numerous reports of child protection concerns relating to the sheer numbers of children being cared for outside of statutory regulations.
"The feedback we are receiving from our members, particularly in rural areas, is that childminders are struggling to compete with informal arrangements," she said.
"They are reporting that fees as low as €10 per day are being charged and in some cases, if the child does not attend, no fee is required.
"Our members are self-employed, compliant with statutory regulations and absorbing all the costs associated with running professional services such as tailored insurance, first aid training, membership of the national body and continuing professional development.
"It makes competing with other businesses that are ad hoc and potentially without statutory regulation virtually impossible."
Galway childminder Pauline McNamee, who is fully registered trained and tax compliant, said it was now "almost impossible" to compete with unregulated childminders.
"We need a level playing field," she said. "How are those of us who are going to great lengths to supply a quality service supposed to compete with people who are simply not investing in theirs?
"I look after children in my home, which I have to insure for such purposes. Annual operating costs are over €1,300 excluding equipment, wear and tear, fuel, food, outings, etc. Parents who use my service value the insured and registered environment.
"There is just no way that it is possible to compete with people offering services for €10 a day."
Early Childhood Ireland and the Association of Childhood Professionals (ACP) have called for better standards.
"Extension of regulations to include all childminders would ensure levels of training, insurance, vetting, etc, a move which is clearly in the best interests of children and families" said ACP's Marian Quinn.
"In the meantime, parents must be cautious and diligent about who they hire to mind their child and make sure that they are asking the right questions before they hand their child over."
Concerns have also been raised about the strain on grandparents providing childcare, after a recent survey found they are more likely to show signs of depression.
Age Action Ireland warned there must be a "fair and even balance" when asking family to care for young children.
"Some people love looking after and spending time with grandchildren but it must be by choice. Simply forcing an older person to care for young children is not acceptable."