Fianna Fáil MEP Barry Cowen has called on the Taoiseach to pursue a better deal for farmers on the nitrates derogation.
In a rare appearance at the party's weekly Leinster House meeting Mr Cowen said he had formally written to Micheál Martin to communicate his concerns.
Mr Cowen's comments come as the party met for the first time since the presidential election result which prompted some TDs to contemplate tabling a motion of no confidence in the party leader.
Speaking about the nitrates directive Mr Cowen stated that the Government's approach risks inflicting lasting damage on rural communities.
He is now seeking a personal meeting with Micheál Martin to discuss the matter.
The MEP also wants the Taoiseach to provide a detailed update on his role in the campaign to retain the derogation.
He told TDs and Senator that this country was never going to win this through strict science or legal definitions.
"This was always going to be a political battle, and we needed to fight it as one," he said.
Mr Cowen added that a deal in principle could be announced as early as Friday but warned a deal for the sake of a deal isn't a victory if it won’t work on the ground.
"From what I’m hearing, this will be a highly conditional derogation, buried under layers of Appropriate Assessments and ongoing reviews.
For the majority of the 7,000 farmers involved - who produce 60% of Ireland’s milk output and form the bedrock of so many other facets of our economy - it could become unworkable," he said.
