Ofgem said it will review the checks and balances energy firms implement when placing customers on pre-payment meters, warning that legal action could be taken.
In a blog, the watchdog's chief executive Jonathan Brearly said he was concerned about the “sharp growth in households struggling to pay their bills being switched over to pre-payment meters, sometimes without their even knowing about it, leaving them without heating”.
It comes after Business Secretary Grant Shapps demanded that energy suppliers stop forcing vulnerable households to switch to pre-payment meters. He also said he would "name and shame" the worst suppliers of this practice.
