Tanaiste Joan Burton has warned that she cannot guarantee a further hike in child benefit in 2016.
The Labour party leader yesterday expressed caution over whether such a measure can be delivered for families in light of continuing difficulties in the eurozone.
The Government was praised by social groups after increasing child benefit by €5 in the recent Budget.
The measure, which only leaked hours before the Budget was announced, will see the payment increase to €135 per every child from January.
It was stated last month that a second €5 hike will be introduced in 2016 "if conditions allow".
But Ms Burton yesterday voiced caution about whether this second hike will come into force.
While insisting that she is "confident" the pledge can be honoured, the Dublin West TD said she "cannot commit to or make very significant promises".
Ms Burton engaged in angry exchanges with Fianna Fail's social protection spokesperson Willie O'Dea after he called on her to apologise for some of the promises "broken" by the Coalition since coming into office.
But speaking at an Oireachtas committee hearing, Ms Burton angrily accused Mr O'Dea's party of "breaking" the economy.
"You should regret all of those people that you drove into unemployment," Ms Burton said.
Mr O'Dea retorted by saying that the Labour party secured votes at the last election "under false pretences".