Nicola Sturgeon has called for crisis talks with gas and electricity companies after British Gas announced its tariffs were rising by an average of £80 a year.
The Deputy First Minister said the 6% increase would plunge thousands of homes into fuel poverty and branded the development "completely unacceptable in an energy-rich country".
British Gas, which trades as Scottish Gas north of the border, is the second of the so-called "big six" fuel suppliers to increase its charges ahead of the winter.
Next week Scottish and Southern Energy's tariffs will rise by an average of 9%, while npower is increasing gas by 8.8% and electricity by 9.1% from the end of November.
The firm has blamed rising wholesale gas prices, which have gone up by around 15%, for the increase.
Ms Sturgeon also called on the UK Government, which has responsibility for regulating energy prices through Ofgem, to get tough on gas and electricity companies.
She said: "These latest energy price rises will have an extremely damaging effect on the finances of Scottish households. I want to meet all the energy companies as soon as possible to discuss price rises.
"For every 5% price increase in energy prices, 46,000 households are pushed into fuel poverty. Not only is this completely unacceptable in an energy rich country like Scotland, it also risks undoing the good work that the Scottish Government is doing to tackle fuel poverty.
"We have invested millions in various measures to help households reduce fuel bills, such as through the Energy Assistance Package, the boiler scrappage scheme, and Universal Home Insulations Scheme.
"Regulating price rises is the responsibility of UK Government, and we urge them, as a matter of urgency, to take a firmer stance with energy companies. Ofgem must publish and implement their updated proposals to protect consumers and ensure companies treat their customers fairly and improve competition between suppliers to rein in price increases."
British Gas announced the increase, which is expected to take effect from November, on Friday.
There was outrage in July after it announced a 23% surge in profits. The company admitted the previous year's price rises helped it rack up operating profit of £345m in the first half of 2012.
The company last raised its prices in August 2011, when gas went up by 18% and electricity tariffs increased by 16%.
This was followed by a drop of 5% in electricity tariffs in January whas en wholesale prices eased, but firms have long been accused of being slow to bring prices down again when their costs fall.
British Gas managing director Phil Bentley, said: "We know that household budgets are under pressure and this £1.50 per week rise will be unwelcome. However, we simply cannot ignore the rising costs that are largely outside our control, but which make up most of the bill.
"Britain’s North Sea gas supplies are running out and British Gas has to pay the going rate for gas in a competitive global marketplace. Furthermore, the investment needed to maintain and upgrade the national grid to deliver energy to our customers’ homes, and the costs of the Government’s policies for a clean, energy efficient Britain are all going up.
"We need an energy efficiency culture in Britain today: rising prices don’t have to mean rising bills. We are offering a huge amount of help to customers to help them cut the amount of energy they use and keep their bills under control. We're also spending more than any other energy company on people who need the most help."