The struggling retail giant says it will cut 2,500 more jobs on top of the previously announced 4,000 as it continues to cut costs.
However, no stores will be closed as a result.
The cuts leave a dark cloud hanging over staff at the two local stores – in Rushmere Shopping Centre and The Quays.
Newry and Armagh MP Mickey Brady described the company’s announcement as “a devastating blow to the workers and their families”.
“This has been a challenging time for workers, particularly those in the retail sector,” said the Sinn Fein representative.
“The fact that Debenhams have moved to lay off staff without consultation with the workers and their representatives is all the more worrying.
“Unions have expressed concern that staff on maternity leave and others who have been with the company for many years have been laid off with no consultation at all.”
He added: “Management at Debenhams need to act urgently to clarify the situation in relation to exactly how many jobs will be lost and at what locations.
“They should also engage with workers and their trade union representatives and keep them informed of all developments.
“Retraining and upskilling programmes should also be offered to any workers losing their jobs to enable them to find alternative employment.”
Shop workers’ union Usdaw said it was “an appalling way to treat staff”.
“We have been contacted by members who say they are being made redundant by conference call, with no meaningful consultation or proper notice period, as required by law,” said union national officer Dave Gill.
Debenhams is currently in administration.
A spokesperson for administrators, FRP, said: “Those affected by redundancy will take no particular comfort from this, but the steps taken are in response to an unpredictable and challenging trading environment and aim to ensure the future viability of the business, while also meeting wider statutory obligations.”