Independent News and Media (INM) is to close its printing plant in Citywest in Dublin.
The Belgian-owned Irish media company told staff on Wednesday that it intends to close the plant.
It currently employs almost 80 people.
SIPTU representatives are seeking an urgent meeting with INM management.
Trade union organiser Martin Mannion said: "The closure of this plant is a massive blow to the workers and the wider print industry in Ireland.
"It is deeply disappointing that a profitable company has made such a decision which affects the entire workforce of nearly 80 people."
He added: "In talks with management our priority will be attempting to ensure that a compulsory redundancy situation is avoided.
"This will include discussing the potential for the continued operation of the facility and the possibility of agreeing a redundancy package that will help protect the financial future of the affected workers."
Belgian newspaper publisher Mediahuis bought the group back in April.
The company publishes the Irish Independent, Sunday Independent and a host of regional titles.
Based in Dublin, INM employs around 800 people and achieved revenues of €191m in the 2018 financial year.