Dublin will face water shortages if water charges are suspended, acting Environment Minister Alan Kelly has warned.
During an impassioned speech to the Dail, Mr Kelly said the decision to scrap water charges was "political, economic and environmental sabotage".
The Labour Party deputy leader also questioned whether Fine Gael and Fianna Fail were acting within the law by suspending charges indefinitely.
Mr Kelly launched a strong attack on both parties, warning the decision would plunge the country back to 1977 - when Fianna Fail abolished domestic rates.
"Fianna Fail had the chance to make a stand on mental health services, on renewal of rural Ireland, to end child poverty or to institute a living wage - yet they have made a stand on an issue that costs people €3 a week. Priorities?"
He also said Fine Gael and Fianna Fail must now tell "law-abiding citizens" who have paid their bills if they will be refunded.
In a stark warning, Mr Kelly said the move to suspend charges would lead to water shortages in Dublin.
"A suspension or scrapping of charges will lose billions of potential investment in water, and I believe we will have water shortages in Dublin in future years."
The Tipperary TD became angry when Deputy Alan Farrell, who was standing in for Ceann Comhairle Sean O Fearghail, told him he had run out of time.
Mr Kelly's Labour colleague Brendan Howlin interjected. "It is his last sentence, show some respect," he said.
Mr Kelly said Ireland had EU obligations to have a charging system and said we risked breaking the law if the plan to suspend charges went ahead.
He also took a swipe at Minister for Agriculture Simon Coveney, without mentioning him by name, over his appearance on Prime Time on March 1. On that occasion the minister raised the idea of a change in policy on water.
"The people who paid, of which there are approximately 950,000 households, may be about to be made fools of and the 340,000 people who already paid for water are being given nothing but disregard by Fianna Fail.
"What's more, Irish Water reported to me that during the election the payment rate actually increased. While not all the data was collected, it was likely that a payment rate of 70pc was likely. Then Prime Time on the first of March happened," Mr Kelly said.
"It is my view that if the suspension/abolition goes ahead, this will cost us more in the long-run.
"There is one vital question, and it is the following: Are Fianna Fail and Fine Gael acting within the law? Does the decision to suspend water charges run contrary to EU law and in particular article 9 of the Water Framework directive?"
Mr Coveney said Fine Gael was still committed to water charges. He said that once the all-party committee reported back to the Dail on the future of water charges TDs would need to make a decision.
"Do we accept independent expert advice about what is best for the country? Or do we retreat behind party political positions designed for electoral gain?" he said.
When Irish Water was asked about the potential implications for its staff of the latest developments it said: "No final policy change resulting from current political talks has been conveyed to Irish Water.
"When we are informed by government of any policy decisions that affect Irish Water we will assess the implications of those decisions for our customers and for our staff."