Confirming provisional findings announced earlier this year, the CMA said that energy suppliers should be ordered to hand details of customers who have been on a default tariff for more than three years to Ofgem.
These details will then be used to build a database to allow rival suppliers to approach these customers, although it is intended that customers can opt out of this database at any time.
A price cap will also be transitioned in for the 4m households on a prepayment meter, which is intended to reduce the combined bill for these customers by £300m a year.
Furthermore, the CMA announced that it intended to strengthen some of the powers that Ofgem had, which should allow the regulator to push through change more efficiently and to keep a closer eye on the marketplace.
The measures are intended to increase competition in the marketplace and ultimately ensure customers can get the best deal possible on their energy bills. The CMA research revealed that customers are currently paying £1.4bn more than they would be in a fully competitive market.
"Competition is working well for some customers in this market – but nowhere near enough of them," said Roger Witcomb, chairman of the energy market investigation. "Our measures will help more customers get a better deal and put in place a modernised energy market equipped for the future."
Today's announcement represents the conclusion of a two year investigation into the energy sector, which focused on whether the so-called big six energy suppliers had been overcharging customers.
The Energy and Climate Change Committee also announced today that it would hold a one-off meeting to discuss the CMA's findings. The hearing is due to take place on 5 July.
"My main priority is making sure that any remedies proposed by the CMA and ultimately enacted by the government are in the best interests of consumers," said committee chair Angus MacNeil. "I remain concerned that too many households – particularly those on big six suppliers’ standard variable tariffs – are paying more for their energy than they should."