MORE than 12m customers face a hike in their fuel bills at the start of the new year.

Now householders have been urged to check out how much more they will be paying.

From January 1, 2006, npower customers are set to see a 13.7% rise in their gas bills and a 12% increase in electricity prices.

Scottish & Southern customers will face a 13.6% rise in their gas bills and a hike of between 8.9% and 12% in the cost of electricity.

Together, the companies have 12.5m customers.

SimplySwitch.com - the price comparison and supplier switching service - said the increases would add more than £80 a year to the average energy bill for npower and Scottish & Southern customers.

Karen Darby, chief executive of SimplySwitch.com, said the "big six" energy suppliers - which also include Powergen, British Gas, EDF Energy and Scottish Power - had all imposed double-digit price hikes since 2004.

They imposed increases of between 23.44% and 36.06% for gas while prices for electricity had risen by between 16.74% and 32.43%.

"New Year's resolutions are hard to keep as they often require a great deal of effort or willpower," said Ms Darby. "One that is simple to keep is reviewing your energy providers to make sure you are making savings where you can."

Ms Darby said householders could save up to 70% on calls by switching phone companies.

And internet users should consider switching or signing up to a new broadband package following a significant fall in prices over the past 12 months.