Representatives of ESB workers who own shares in the company urged the Minister for Energy, Communications and Natural Resources, Eamon Ryan, yesterday to finalise a system for trading the stock.

Around 4,000 of 10,000 workers in the State company who bought the shares 10 years ago have left and are entitled to sell their stake to employees of the company.

Members of the employee share option plan (Esop), which represents the workers, met Mr Ryan yesterday and asked him to work with his colleague, the Minister for Finance, Brian Cowen, on creating a market for the shares.

The workers own 5 per cent of the ESB. Those who have left want the market structured to limit the risk of loss on their investment.

The structure of any market will need to be agreed between Mr Ryan's and Mr Cowen's departments.

Yesterday's meeting was the first between the Esop and Mr Ryan since his appointment last summer.

The shareholders' body also warned him that Government plans to break up the ESB would weaken the State company.

Since early last year, the Government has been planning to transfer ownership of the national electricity grid, which transmits power from generating plants to the distribution network and ultimately to customers, to a separate company, Eirgrid.

The ESB still owns the grid, but Eirgrid manages it.

The Government believes the break-up, which is also opposed by the ESB's unions, will help boost competition in the electricity market.

The employee share option plan delegation pointed out to Mr Ryan yesterday that many EU states are now opposed to breaking up their large utilities as it will leave them vulnerable to takeover by more powerful players, which will in turn reduce competition.