The UK energy market is like "a volcano about to erupt", according to switching service energyhelpline, which has said prices could go up by 5 to 10% in the next few months.
The switching service said senior executives at some of the Big Six suppliers "have been strongly hinting that there are more price rises to come".
It pointed out that one executive stated that more price rises are "inevitable", while another said that "it is an indisputable fact that energy costs are rising".
Energyhelpline said a series of tariff changes have also been brought in by a number of suppliers that "appear to have the intention of retaining existing customers once a price rise hits".
For example, early last month EDF Energy launched the longest fixed-price energy deal on the market, a three-year fix enabling customers to lock in the price they pay until the end of November.
But customers have to pay more for the certainty as the deal was £32 a year more than npower's Price Fix September 2016, which was previously the longest fix on the market. And it was a whopping £215 more than the cheapest fixed deal available at the time - Flow Energy's Thames Fixed Online Sept 2014.
Mark Todd, director of energyhelpline, said: "There are clear indications that energy price rises are close. I would not be surprised if they are announced within the next two months. In fact you could describe the energy market as a volcano about to erupt. The lava may soon descend on consumers across the country wiping out their household budgets.
"We know from experience, when one supplier announces price rises others follow, and in the last three years these have come in the summer and autumn. It may be mere coincidence, but there are distinct advantages to introducing a price rise before the cold weather hits, as the increased rates kick in as gas and electricity usage rises."
He added: "The conversation behind closed doors within the industry is all about who will dare to move first and how hefty the price rises will be."