Up to 75 jobs are under threat after Scottish media group Johnston Press earmarked two printing operations in Northern Ireland for closure.
The group said affected staff would be offered redeployment, relocation or redundancy.
Peter Williamson of the Amicus union
Just under a year ago the company acquired Local Press Ltd, publishers of the Belfast-based News Letter- founded in 1737 and the oldest newspaper in the world in continuous daily publication - and the Derry Journal.
In the same month it bought Morton Newspapers which publishes 17 weekly and five free titles in the North.
The company said following a strategic review of its operations it had identified the Derry press facility as no longer fulfilling its future business requirements.
The age and condition of the press meant it no longer met the needs of readers and customers, it said.
"The cost and economics of a replacement press and the fact that there is significant existing capacity elsewhere in Ireland, has made further investment in the Derry press facility uneconomical," said a statement from divisional managing director Jean Long.
It is proposed the closure of the site will start from September 30th. At the same time the company is understood to be planning the closure of a second press in Belfast.
Peter Williamson of the Amicus union said the number of potential job losses had come as "a big shock".