A motion calling on the Government not to proceed with cuts to the One-Parent Family Payment was defeated last night in the Dáil.
The changes to the payment, which will see it stopped when a child reaches the age of seven, came into effect today.
Sinn Féin tabled a motion calling on the Government to reverse the changes to the payment, saying it would push lone parents further into deprivation.
The motion, proposed by Aengus Ó Snodaigh, also stated that the promised childcare structure was not in place.
During the debate, Opposition deputies said lone parents were facing substantial cuts, with Independent TD Stephen Donnelly citing one person who was set to lose €140 a week.
However, Labour members defended the move, saying the reforms aimed to lift lone parents out of the poverty trap.
Joanna Tuffy said Mr Donnelly's example did not take into account the Back to Work dividend, which aims to help families move from social welfare to employment.
The Sinn Féin motion was defeated by 79 votes to 36.