Workers based in Durham, in the north-east of England, were informed of the decision that will affect around 200 members of staff whose roles will be changing.
The gas and electricity supplier's said the move, which involves its team based at Tees House in Peterlee, will help improve the firm's services.
"At the moment, our customer service teams are experiencing really high volumes of calls and correspondence and so we've decided to ask one of our existing partners to help us handle customer letters and emails. This will free up almost 200 employees, who'll then be able to help take more calls from our customers," a spokesperson told PTI.
The decision means those working in the customer "letter-writing and email response" side of the energy business have been told they will be relocated into the call-centre division, which has left some workers upset.
"There were people in tears when the company told us what was happening," a worker said, not wanting to be named.
"We understand that by moving the work to India, Npower expect to make pay savings of about 60 per cent. We realise jobs are not being lost, but we are concerned that many of the workers have no experience working in telesales and are suddenly going to be in an environment they are not used to and don't want to work in," a GMB spokesperson said.
Swindon-headquartered NPower is a London-listed energy firm and one of the leading suppliers of power across the UK.
