An announcement is expected to be made tomorrow, which it is believed will affect a number of call centres across the UK.
Speculation has been rife for weeks that around 2,000 jobs were under threat because of outsourcing plans and moving work abroad.
It is understood that frontline call centre operations will be outsourced to a third party in the UK, with back-office work moved to India.
The expected news follows a number of cost-saving announcements from npower since its German owner RWE said earlier this month that 6,750 jobs would be cut across Europe.
Neither npower nor unions would comment on the speculation, but an industry source told the Press Association that 1,400 jobs will be offshored to India and around 570 transferred to another company.
The move is likely to spark renewed anger from politicians over the state of the energy market, and soaring energy bills faced by consumers.
An npower spokesman said: "As we announced a couple of months ago, npower has been undertaking a major review of sites, operations and people across the UK.