The decision by Labour's five senators to abstain in a vote on a Fine Gael private member's motion opposing the closure of the Carlow sugar plant has led to tension between the two parties.
Carlow-based Fine Gael senator Mr Fergal Browne told The Irish Times yesterday that he was "puzzled and annoyed" at the Labour decision.
"I cannot understand it given the views of SIPTU, the stand taken by Labour in the Dáil, and the fact that Labour councillors participated in last week's protest march in Carlow."
The motion, which was moved by the Fine Gael spokesman on agriculture, Mr Noel Coonan, noted the tremendous contribution made by the Irish sugar beet industry to the economic and social development of rural Ireland, and expressed regret at Greencore's announcement to cease production at the Carlow plant in March.
It called on the company "to reverse this decision and take no other such actions until the EU reforms concerning the Irish sugar quota are concluded".
It also urged the Minister for Agriculture and Food, Ms Coughlan, to resist strongly any EU proposals which would threaten the long-term viability of sugar beet growing in Ireland.
Defending Labour's decision, Mr Michael McCarthy, a senator basted in Dunmanway, Co Cork, said his party had abstained because the motion might have impinged on the future viability of the Mallow plant.
"It was a question of geography," he added.
Speaking during the debate, on Wednesday night, Mr Browne said that the motion was deliberately non-contentious and simple.
"It is regrettable that the Government has decided to amend the motion," he added. "In my view it has turned its back on the factory in Carlow."
Cork-based Labour senator Mr Brendan Ryan, in his contribution to the debate, said it was a pity the Seanad only discussed such issues in the middle of a crisis.
"It is high time we began to talk about a future for all agriculture and food industry based on the reality that within five, 10 or 20 years it will be based on a free trade arrangement," he added.
In the Dáil on Thursday, the Kildare South Labour TD, Mr Jack Wall, urged the Minister to seek to have the proposed closure put back to next year.
Ruling out direct intervention, Ms Coughlan said: "I will not be in a position, regardless of whether I have a golden share, to tell the board of Greencore what to do with regard to the day-to-day management and working of the company."