The Department of Education has estimated an additional 1.7 million euros in annual costs for the controversial school phone pouch scheme.
The figure is based on an estimated 20% replacement rate for the pouches every year.
It comes on top of a nine million euro allocation in the Budget for a fund which would enable schools to purchase pouches to hold pupils’ mobile phones, in a bid to minimise disruption.
In the Dail on Wednesday, Mary Lou McDonald criticised the overall plan and the projected recurring costs – as she put forward a larger figure of two million euros annually.
Ms McDonald said it is an example of the Government being a “serial waster of the public’s money”.
Speaking during Leaders’ Questions, she said the public is angry at the lack of accountability on spending.
“This shows, again, that your Government can’t be trusted to spend the public’s money wisely.
“You can’t be straight with people about your waste and you refuse to be accountable for your mess.”
Ms McDonald said documents obtained by her colleague, Pearse Doherty, show the Government was presented with several options for dealing with mobile phone use in schools.
She said these included leaving phones in bags or lockers, or having them handed into a central point – each at zero cost.
“Instead, you have gone with an option that will cost the taxpayer nine million euros initially, and then a further two million euros every single year,” she said.
The Department of Education later acknowledged an estimate of 1.7 million euro annual costing for replacing the pouches.
Ms McDonald said the money for the phone pouches should instead be invested in youth mental health services.
Taoiseach Simon Harris defended the overall plan, which he said would cost 20 euros per student.
He said the policy came from engagement with school principals and the mental health concerns of students themselves.
He also said the scheme is not obligatory or mandatory, adding: “Nobody’s going to demand a school take pouches – this is if a school wants to avail of this.”
While not responding to Ms McDonald’s central claim around annual costs, he added: “It’s about 20 quid per student. A 20 euro investment in the mental health and wellbeing of a student.”
A similar scheme has been rolled out in Northern Ireland, where Sinn Fein is in Government.
Mr Harris asked whether it is Ms McDonald’s policy that the pouches are “good” in Northern Ireland but not appropriate in the Republic.
“The most breathtaking thing about your presentation is that you’re rolling out a similar initiative but, you know what, it’s costing a hell of a lot more.”
He added: “Will you call on the Sinn Fein Minister for Finance in Northern Ireland today to speak to her Executive colleague and stop the rollout of the phone pouches in Northern Ireland?
“Because in Northern Ireland, you’ve already spent a quarter of a million pounds sterling on the provision of phone pouches.”
Ms McDonald responded in the negative in relation to Mr Harris’ query, advising him to “take it up with the DUP” as they hold the education portfolio in Northern Ireland.
A spokesman for the Department of Education said the pouches are “easy to use, cost-effective and better for equity among students”.
He said the Department had engaged with a number of schools already using pouches who found they were “very positive” and “transformational” for school life.
“A working estimate of 20 euro per pouch was outlined to lead to a cost of around 8.57 million euro in the first year of use.
“The briefing estimated a replacement rate of about 20% each year, meaning an annual costing of 1.7 million euros.
“It should be noted that these figures were used to estimate the ongoing funding requirements of the initiative along with some additional contingency funding also being provided for.”