The Irish Prison Service is dealing with more than 1,600 proceedings from former prisoners over toilet use.
While no money has been paid out, the taxpayer has already footed a substantial legal bill fighting claims.
The Irish Prison Service told TDs that the claims for compensation have been lodged in court by former prisoners in respect of the fact that they did not have in-cell sanitation during their period of detention.
“In 2017, €351,000 of the €1 million related to legal costs incurred by the State Claims Agency in defending those cases,” she said.
She acknowledged that the bill was very large.
The cases refer to Mountjoy but slopping out is still being carried out in part of Portlaoise Prison. A new prison wing is proposed to end the practice.
The High Court ruled in 2017 that the practice of slopping out endured by a prisoner in a shared cell at Mountjoy Prison breached of his constitutional right to privacy.
The court also ruled the prisoner in question was not entitled to compensation. The court ruled the practice did not amount to inhuman and degrading treatment.
The matter is still before the courts.