Barclaycard is closing its customer call centre in Manchester, which employs 630 staff, and is shifting some of the work to offshore centres in India.
In a statement Barclays says staff at its Manchester call centre have been told the unit will close on 16 July.
After this date, customer calls will be routed to Barclaycard's facility in Teesside and to its call centres in Mumbai and Delhi, India.
The bank hasn't stated how much of the work will be offshored but financial services union Amicus claims 200 of the 630 jobs at the Manchester call centre will be sent overseas.
In a statement, Amicus official Steve Pantak says: "At a time of increasing pressure on all staff in Barclaycard we believe it to be totally inappropriate for this large and highly profitable employer to be announcing closures and job losses."
But Barclaycard chief executive, Antony Jenkins, argues that the business is becoming more global and to stay successful "we must change how we operate to reflect this".
Earlier this month banking group Lloyds TSB said it was closing its contact centre in Mumbai after interactive voice recognition (IVR) technology introduced last year reduced the number of calls processed manually by 25%.