SSE has become the last energy firm from the Big Six to hike bills, prompting a minister to call on consumers to “vote with their feet”.
SSE has blamed wholesale price increases and Government policy for the increase in its tariffs.
The group is increasing electricity and gas bills by an average of 6.7%, or £76 per year, in a move affecting 2.36 million customers.
Claire Perry, energy and clean growth minister, said: “It is extremely disappointing that SSE has decided to announce this unjustified price rise – the highest yet from the Big Six – ahead of the new law coming into effect later this year.
“Consumers should vote with their feet. Switching suppliers will always help consumers get the best deal.”
The price changes will come into force on July 11, with a 5.7% rise for gas and 7.7% for electricity bills.
This will equate to an average increase of around £1.50 a week for customers buying both gas and electricity.
Stephen Forbes, chief commercial officer of SSE Energy Services, said: “We deeply regret having to raise prices and have worked hard to withstand the increasing costs that are largely outside our control by reducing our own internal costs.
“However, as we’ve seen with recent adjustments to Ofgem’s price caps, the cost of supplying energy is increasing and this ultimately impacts the prices we’re able to offer customers.”
The price hike from SSE comes after Npower, EDF, British Gas and ScottishPower all raised prices.
More than nine million households will be hit when the tariff rises from the energy firms come into effect over the summer, which economists have said will likely push up inflation.
Energy companies have blamed the Government’s planned introduction of a cap on standard variable tariffs for increasing prices.
Profits at SSE took a knock last year as it lost 430,000 customers and was stung by charges linked to the merger of its retail arm with rival Npower.
The group reported a 6% fall in adjusted pre-tax profit to £1.45 billion in the year to March 31, while bottom-line profits tumbled 39% to £1.09 billion.
The company was hit with more than £60 million in IT costs related to its Npower deal.
Martin Lewis, founder of MoneySavingExpert.com said: “Yet again like sheep, with energy firms, when one moves the rest all follow. Yet the reality is they are wolves in sheep’s clothing.
“Anyone on a Big Six standard tariff is ripping themselves off by failing to take action. Do-nothings pay massively more than the do-somethings.
“Switch firm and you could cut bills to almost £800 a year, even with the same usage.”