THE ESB will try to win back customers poached by cheaper rivals by offering them deals if they sign up for both gas and electricity.
The energy regulator will announce later this week that the ESB will finally be free to set its own prices as of April.
ComReg commissioner Dermot Nolan told the Irish Independent that an announcement over deregulation would happen within days but a "full-scale price war" was not expected.
Deregulation is taking place because 870,000 electricity customers have switched supplier in the last two years. Some 730,000 of these have left ESB, with the remainder switching between Bord Gais and Airtricity.
The ESB confirmed it would focus on winning back customers by entering the dual fuel market, where householders sign up for both gas and electricity from the same supplier.
An ESB spokesman said that they would announce details of new offers in coming weeks, but it would be premature to do so before ComReg formally announced deregulation.
"Clearly we don't want to lose any more customers and this will give us the flexibility to compete," he said.
Mr Nolan said they would monitor the market to make sure that vulnerable and older customers who found it difficult to switch were not put at a disadvantage by seeing their prices increase.
Energy expert Simon Moynihan, who runs energy comparison website bonkers.ie, said the dual fuel market would be the obvious target for ESB as it was more lucrative and gave the opportunity to lock customers in for 12 months.
"I would not expect a full-scale price war with deregulation, but the market will be more competitive and there will be a lot of offers," he said.
Around 40,000 customers a month in Ireland continue to switch gas or electricity, meaning there is still a huge amount of movement in the market here, Mr Moynihan said.