Judgment has been reserved in an application by independent electricity firm e-Power for judicial review of a decision by the commissioner for electricity regulation, Mr Tom Reeves, to change a system for the sale of ESB power to the private suppliers.

Mr Justice Murphy will rule on Wednesday whether Mr Reeves's decision to limit the availability of power at favourable "top-up" rates can be implemented.

E-Power - which purchases such power from the ESB - has argued that the proposed move "makes a mockery" of competition, but this was challenged by Mr Reeves and by the ESB.