The firm said it was looking to reduce staff numbers across its non-customer facing departments as part of efforts to improve efficiency and service for customers.

The job cuts are part of a mid-term plan to save around 100 million pounds.

"We’ve undertaken a rigorous review of our options to ensure we keep costs as low as possible, become a more agile organisation and remain a sustainable business in the UK," said Michael Lewis, chief executive of E.ON UK.

"In discussion with our trade unions we've identified potential reductions of around 500 roles across the UK and we're committed to achieving these reductions on a voluntary basis wherever possible," he said.

E.ON said there are "numerous challenges" in the energy market, including a UK government-imposed cap on the most common form of gas and electricity tariffs for millions of British households.

Due to the voluntary nature of the proposed job reductions, it is not possible to say yet how many people at individual sites or specific business areas will be affected by the proposals, the company said.

Germany's E.ON employs more than 9,400 people in Britain.

(Reporting by Nina Chestney; editing by Jason Neely)