The announcement of the cuts across the RWE group and its partners is due this week, it was first reported by Sky News.
Npower employees 11,500 people in Britain people, meaning the cuts could reduce its head count by around 20 per cent.
In February Npower become the latest "big six" energy supplier to whittle down customers' gas bills. Energy companies have faced mounting calls calls for firms to pass on record low wholesale gas prices to customers.
It comes as energy prices are plumbing historic lows, with US oil prices crashing below $27 per barrel for the first time in 2003 earlier this year.
In 2015 RWE reported a loss of £48m for the first nine months of the year. RWE is set to publish its annual results on Tuesday.
Npower declined to comment.