A final report on a major investigation into the UK's energy sector by the competition watchdog is set to be published.
The report by the Competition and Markets Authority could include requirements to introduce a temporary cap on prices for households on pre-payment meters and a database of those who have not switched supplier recently.
The measures were among provisional proposals to improve the market for consumers set out by the CMA earlier this year, as it warned customers had been paying £1.7 billion more than they would in a competitive market.
It found that while some people shopped around for good deals, around 70% of the domestic customers of the six largest energy firms were on the more expensive "default" standard variable and were being taken for granted by suppliers.
It set out plans to launch an Ofgem-controlled database allowing rival suppliers to offer those on standard variable rates for three years or more better deals - though this raised concerns over a potential increase in spam to customers.
The proposals also included a temporary price cap for four million households on pre-payment meters until 2020, saving an average of £80-£90 for each customer, or a total of £300 million.
Price comparison websites would be able to broker exclusive deals with suppliers, rather than having to show all deals, and Ofgem's four tariff limit for companies brought in to simplify the market would also be removed under the proposals.
The report by the CMA, coming out on the morning of the EU referendum result in what has been acknowledged as not ideal timing, follows a two-year review into the energy sector.
It was launched amid rising prices for consumers and concerns over the dominance of the Big Six suppliers, with then Labour leader Ed Miliband threatening to bring in a price freeze and split up the big energy firms if Labour won power.