An urgent Government response was called for yesterday after 200 workers in Tallaght, Dublin, were told they are to lose their jobs this summer.
Management at APW Enclosures, which makes computer frames, told union shop stewards that the plant would close in June.
Negotiations are to begin immediately on redundancy terms and on an offer by the company to help its staff secure alternative employment.
Mr John Bolger, district secretary of the ATGWU, which represents the non-office workers at the plant, said management had said it was too expensive to continue manufacturing in the Republic and it was moving its activities elsewhere.
There had been rumours for some time that the operation was to move to Poland, he said.
Mr Bolger said that, while the company had offered to assist workers in finding alternative employment, it would be difficult for staff to find jobs of similar quality.
The company had been a good employer, providing pensionable, "reasonably well-paid" jobs, he said.
Some of those losing their jobs had up to 18 years' service in APW and a predecessor plant on the same site.
The company also has plants in Cork and Galway, but it is understood these are not affected by the decision announced yesterday. Management at APW could not be contacted last night.
Mr Bolger accused the Government of having no policy to deal with continuing job losses in the manufacturing sector, which he said was "haemorrhaging to death".
The Labour Party leader, Mr Pat Rabbitte, a TD for the Tallaght area, said the planned closure highlighted the rate of attrition in job losses in low- to semi-skilled employment.
The pattern of relocation or closure in traditional sectors had been concealed to some extent by strong job creation in other sectors, he said.
"However, this is cold comfort for the people actually losing their jobs, and only investment in up-skilling will enable them to find new jobs," he said.
Mr Rabbitte claimed the Government and employment agencies seemed resigned to the loss of manufacturing jobs. "Urgent strategies involving investment in training and up-skilling must be put in place for the workers affected," he said.
