Lone-parents groups say as many as 11,000 working families stand to lose out under welfare reforms due to come into force next month.
Under the changes, single parents in receipt of social welfare will be required to seek employment or training as soon as their youngest child reaches seven years of age.
While the Government says the move is aimed at enabling one-parent families move out of welfare dependency, it acknowledges at least 4,000 of the 30,000 parents in part-time work will suffer an income loss.
But campaign groups such as One Family and Spark insist up to three times that number will end up losing out.
Those hit hardest, they say, will be those already in part-time employment who stand to lose out by amounts ranging from anything between €10 and €140.
‘Incredibly serious’
“We estimate that up to one third of lone parents affected will lose out, which is incredibly serious,” said Karen Kiernan of One Family.
“If this is a policy about getting people into the labour market, then it’s simply counterproductive.”
Among the key issues under the new regime - due to come into effect on July 2nd - are lower income disregards and access to the family income supplement.
The Department of Social Protection says thousands of lone parents who increase their number of part-time working hours to 19 will be better off.
This will entitle them to the family income supplement and a new back-to-work family dividend.
Officials say they expect many lone parents will increase their hours of employment and, ultimately, be financially better off than they were before.
Low hours contracts
But Spark, the lone parents campaign group, say many lone parents aren’t able to increase their working hours to 19 because they are in low hours contracts.
“Lone parents are being told they need a letter from their employers saying they’ll increase their working hours to 19,” said Spark’s Louise Bayliss.
“The reality is that it’s very hard to get an increase in hours. These are employees in often very vulnerable circumstances.”
In addition, tougher rules over income disregards and how working hours are spread over a week will penalise thousands of part-time workers, she said.
Campaign groups have called on Tánaiste and Minister for Social Protection Joan Burton to pause the introduction of the reforms or bring in new budget measures to ensure working parents do not lose out.
But well-placed Government sources say there is little prospect of changes as next month’s reforms are the final element of a process which began two years ago.
Ms Burton has argued the existing welfare scheme has been unsuccessful in lifting lone parents out of poverty because it is passive in nature and has created a dependency on welfare.