More than 330 people are to lose their jobs with the closure of the country's last remaining sugar factory at Mallow in Co Cork.
The closure of the plant was announced this afternoon by Greencore which owns Irish Sugar.
Greencore said it would shut the Mallow plant in May.
It blamed the closure on the package of reforms agreed for the sugar industry by European Union farm ministers last December.
Greencore has enough sugar to supply Irish industrial and retail customers until November 2006, and is putting plans in place to supply these customers under the Siúcra and McKinney brands thereafter.
The Chief Executive of Greencore, David Dilger, thanked employees and said the closure was inevitable due to the EU sugar regime change.
Following the announcement Irish Farmers' Association President, Padraig Walshe, said much of the blame for the demise of the Irish sugar industry rests with Greencore.
Mr Walshe said that over the past ten years, Greencore had drained over €300m in profits from Irish Sugar without planning for a viable future for the industry.
Crisis for Mallow: TD
Speaking on RTÉ Radio's News At One, Fianna Fáil TD Ned O'Keeffe said he had expected bad news for the plant and he did not think anything could be done to rescue the situation.
He said it was a crisis for Mallow and the region, and efforts would have to be made to provide more jobs for the area.
The Carlow sugar factory was closed early last year, leaving Mallow as the only survivor of four original sugar plants.
The EU reforms involved major cuts in subsidies, but it was felt that sugar production would be profitable for the next two years.