The details of an email Mr Stagg sent to a critic of the cuts embarrassed Tánaiste Joan Burton, as she tried to defend in the Dail the changes to lone-parent payments.
Reading out parts of the email, Fianna Fáil leader, Micheál Martin, said it highlighted the unfairness of the cuts. Some lone parents are €70 a week worse off, as they say they cannot make up the shortfall by working extra hours, due to a lack of affordable childcare.
Quoting from the Stagg email, Mr Martin said the Labour chief whip had said he only voted for the cuts because he was told that a much-improved childcare system would be in place before they were imposed by Ms Burton.
Mr Stagg stated in the email: “I simply fail to see how cutting the income of the very ones who are making a real effort to improve the lot of their families, and themselves, helps in some way to get out of the poverty trap.
"It clearly has the opposite effect. I will continue to press for a reversal of this bad decision.”
Sinn Féin’s Peadar Tóibín accused Mr Stagg of “double duplicity”, because he voted for cuts he opposed and then whipped fellow Labour TDs to back the reforms.
Thrown on the defensive by the revelations, Ms Burton said that Mr Stagg had insisted “the reform is a good reform”.
Ms Burton said the reform would be good for lone parents, as it was intended to raise their incomes above €400 a week, with a combination of increasing, part-time working hours, to 19 a week, and family income supplement, depending on the number of children.