International textile firm Fruit of the Loom plans to close its Irish operations over the next four to five years and move them to Morocco where costs are lower.
The closure means 630 jobs will eventually go at plants in in Co Derry and Co Donegal.
"Over recent years our European manufacturing configuration has changed significantly as we have undertaken productivity initiatives in an attempt to secure our long-term competitiveness," Fruit of the Loom, owned by US holding company Berkshire Hathaway, said in a statement.
"However, external pressures . . . have made this decision unavoidable. Despite our best efforts, our Irish manufacturing base is no longer cost competitive."
The company blamed a World Trade Organization decision to remove quotas on imports from Asia, price deflation in Europe and wage and utility price rises in the Republic for the rising cost of manufacturing.
The firm's spinning, knitting and dyeing operation would be closed down over the next four to five years and relocated to Morocco, where the group employs 1,700 people.
Fine Gael Senator Mr Joe McHugh called on the Government and the Northern Ireland administration to launch a cross-Border jobs initiative and tackle the growing unemployment crisis in the region.