Sugar beet farmers and suppliers are demonstrating at the sugar factory in Carlow town today over plans to close the facility.
The closure follows a decision by parent company Greencore to concentrate all sugar production at its plant in Mallow.
The closure, which is being described by the company as a commercially driven rationalisation programme, will mean the loss of 189 full-time jobs in Carlow and a further 138 part-time jobs within Irish Sugar.
The decision to hold today's protest was taken at a meeting of growers last week that was attended by over 1,000 people.
Protesters are seeking to exert commercial and political pressure on the company and on the Government, which is a "golden shareholder" in the enterprise.
The plant, the first modern sugar processing plant set up by the new Free State in the mid 1920s, is to close on March 11th.
But Irish Sugar will retain a number of key non-production operations in Carlow, where it will employ 63 people, although all processing will be in Mallow, Co Cork.
Mr Denis Naughten of Fine Gael has called on the Minister for Agriculture to avert what he described as "the wind-down of the Irish sugar industry".