Fianna Fáil has been accused of having "no passion" in its bid to suspend water charges.
The claim comes from the Anti-Austerity Alliance, which says the future of charges should be decided in the Dáil - and not in private talks between the two largest parties.
TD Mick Barry says Fianna Fáil should be wary of a backlash from voters if they back down in their bid to abolish Irish Water, and cast doubt on their anti-water-charge credentials.
"I don't believe for a moment that Fianna Fáil are passionate on this issue," he said
"Why would they be, when they were the originators of the idea of the water charge, discussed it at the Cabinet table before the 2011 General Election, and haven't actually called for the total abolition of water charges, but for their suspension."