Last-minute negotiations between the energy regulator, Mr Tom Reeves, and the independent national grid operator, EirGrid, are expected to resume this morning before the start of a High Court hearing.

Talks between legal representatives for both sides went on all day yesterday and there were signs that the issue could be resolved without expensive court proceedings. The ESB and EirGrid have reached agreement for the final separation of the ESB from the operation of the national electricity grid. However, the regulator has not given his consent to the deal agreed by the two firms.

Mr Reeves is understood to have several difficulties with the proposed deal and, in particular, to believe there would be a duplication of functions. This, he fears, would add to costs and increase electricity prices.

EirGrid refused to agree to a directive issued by Mr Reeves last year and this led to the legal process set to culminate in today's hearing. Numerous attempts to resolve the matter have failed. The Government is said to be anxious that an agreement is reached before the initiation of expensive court proceedings. Fears have been expressed that a full court battle over the issue could lead to costs of €5 million. The ESB is a notice party to the action.

The grid is being removed from ESB's responsibility in an effort to ensure the fair operation of the system as competition is introduced.