Some 240 people will lose their jobs in Fermoy, Co Cork, with the closure of French company FCI Ireland.
The company makes electrical connectors for the car industry and employs 260 people in the town.
FCI opened its Co Cork factory in 1996. Despite successful trading for a number of years, the company said the decision to end manufacturing is part of a global restructuring and that it is moving its manufacturing to low-cost locations.
The Fermoy operation will close by the end of next year.
It is understood that manufacturing is being relocated to Asia. FCI said it will do all it can to secure new jobs for staff.
Management said the company plans to keep on 20 staff at the plant in the customer support department.
Senator Paul Bradford of Fine Gael said the news was a "devastating blow", and he said that the Department of Enterprise, Trade and Employment should engage with the firm to try to save the jobs.
"North Cork is fast becoming an unemployment blackspot. FCI's announcement comes on the back of the demise of Greencore, the loss of over a thousand jobs at Dairygold and the announcement by BUPA that it will pull out, leaving another 350 workers without employment.
"In just two years, 2,000 jobs have fled Fermoy, leaving the entire area in dire straits," Mr Bradford said.
Labour Party councillor Sean Sherlock said the immediate priority must be to ensure an adequate and beneficial redundancy package for these staff.
"Unfortunately this closure is typical of a wider trend in the Irish economy whereby traditional manufacturing jobs are being lost with no new ones becoming available. Workers are left with having to re-train and enter different industries," he said.
Additional reporting: PA