People are being warned to look out for fake emails and texts claiming to offer discounts on energy bills.
A number of different scams have been circulating, including some that appear to be from the energy regulator Ofgem.
The government has announced that a £400 energy bill discount will be available to all households.
But this will be automatic and people should not give away personal details in order to apply.
Energy bills have been rising sharply – it had been forecast they could reach £4,200 in 2023 – although the government has since said typical household energy bills will be capped at £2,500 annually until 2024.
Ofgem has asked energy suppliers to be clearer on potential customer fraud on their websites.
The messages invite people to apply for the £400 “non-repayable discount” and instruct the recipient to follow a link to a fake Ofgem website to then provide personal details.
It then encourages people to set up a direct debit to receive the money.
An Ofgem spokesperson said protecting consumers is their top priority: “It is alarming that vulnerable customers are being preyed upon in this way when people are already struggling so much.
“On top of issuing our own warnings and advice, we have asked all energy suppliers to ensure clear and up-to-date information on scams is easily accessible on their websites.
“We take these attempts to exploit consumers very seriously.“
Sites sending out scam messages that have been identified by the BBC include: