The Glen Electric plant blamed the redundancies on the effects of the downturn combined with growing competition from the Far East.
The firm, which makes panel heaters, informed employees of the lay-offs this afternoon.
A spokeswoman from Invest NI, which has supported the company, said it had been made aware of the announcement.
Glen Electric NI is an arm of the international electric heating business company Glen Dimplex Group.
It employs around 500 people at sites in Newry, Portadown, and Craigavon.
