E.ON Energy has become the latest of the big six UK energy suppliers to up its prices.
E.ON have raised electricity bills by 11.4%, while gas bills will be raised by a larger margin of 18.1% and will come into effect from 13 September.
They are the fourth of the big six UK suppliers to announce hikes, after Scottish Power, Centrica and Scottish and Southern Energy announced rises over the past few months.
As with the others, E.ON has blamed the increases on the 30% rise in wholesale prices this year.
However, reports suggest that wholesale prices are currently at their lowest for the entire year, dropping down due to recent global economic downturn.
There have been renewed calls for the competition commission to become involved over unfair rises.
Mike O’Connor, chief executive of Consumer Focus, said: “Wholesale costs are around a third lower than their 2008 peak, yet consumer prices have reached an all-time high.
It is seen as just a matter of time before Npower and EDF Energy follow suit and also raise prices.