The elderly, small business owners and low income earners will be the hardest hit by soaring power and gas prices in the ACT.
On Wednesday night the territory's competition watchdog announced price hikes that could add hundreds of dollars to power bills every year.
From July 1 retail electricity bills will rise by around $333 per year for the typical household, while residential natural gas bills will increase by $247 on average.
The news comes on the back of an announcement in the ACT budget that property owners face rates rises of around 7 per cent per year.
The ACT Energy Policy Consortium described the increases as a "massive blow" to struggling Canberrans.
Those most affected would include the elderly, those on government benefits and small business owners and community providers, a spokeswoman said.
"Community service organisations - for example aged care, early childhood education and day treatment providers – are a significant part of the ACT economy and have limited capacity to pass on cost increases in fees or charges.
"Indeed, many of these organisations have had funding cuts. Increased electricity costs will impose a further strain on already limited budgets."
The ACT Independent Competition and Regulatory Commission said it was forced to hike the price of electricity after "substantial jumps" in the wholesale market.
Retail electricity prices have been increased by an average of 18.95 per cent per year, or $6.40 per week, while retail gas prices have gone up by an average of 17.3 per cent, or $4.75 per week.
"Australia's wholesale electricity market has seen dramatic price rises in 2016 and 2017 and this unfortunately means that retail electricity prices will increase sharply," the commission said.
"It is important to note that almost 88 per cent of total costs are determined outside of ActewAGL Retail's control and therefore the commission's oversight.
"This includes electricity purchase costs and network costs."
In a joint statement, Chief Minister Andrew Barr and Sustainability Minister Shane Rattenbury criticised the Federal Government for its inaction in preventing the "disappointing" price hikes.
"These increases are driven by the failure of the national electricity market, the closure of the coal fired plant at Hazelwood and, critically, a failure of national leadership," they said.
"The continual ideological debate at the national level has led to a sustained period of inaction over the very real issue of sustainable and affordable energy prices in this country.
"Despite the increase, ACT households and businesses will continue to have some of the lowest cost and most reliable electricity in the country.
"Canberrans will still be paying hundreds of dollars less than our neighbours across the border in NSW."
ActewAGL chief executive Michael Costello attributed the increases to "unprecedented" rises in wholesale energy costs.
"This in turn has created an investment climate of such uncertainty as to culminate in a doubling of wholesale electricity prices over the past year," he said.
The utility company said it would be establishing an Energy Support Fund, worth $250,000, to help consumers struggling with the rises.
This would fund energy vouchers for those in desperate need of electricity, a solar grants program for community organisations, and a troubleshooting hotline.
The government said it would match this contribution dollar for dollar.
"Our main message to the community is if you're struggling to make ends meet, don't go without energy, please contact us as there are things we can do to help," Mr Costello said.