ALAN KELLY has said it would be 'environmental treason' to suspend or abolish water charges - but says if the charges are scrapped, those who paid should be refunded.

In a blistering speech in the Dáil, likely to be his swansong as the minister responsible for the charges, Kelly predicted future water shortages if charges were done away with.

"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," he said.

"Given what I'm hearing if there is any fairness, the law-abiding people who could afford to pay and did pay will have to get their money back. That will mean Irish Water will have to reprocess well in excess of two million financial transactions. Is that common sense?

"But whether the charge is being suspended or abolished, I believe Fianna Fail and Fine Gael need to tell people how and when they will give them back their money."

He also claimed that, while payment figures for the fourth quarter of 2015 have yet to be released, the preliminary information showed 70% of bills had been paid.

This would compare quite positively to previous figures, which showed that only 61% of all customers had paid any of the three previous bills.

But - referring to Simon Coveney's later admission that the charges could be part of a government compromise - Kelly added: "Then Prime Time on the first of March happened!"