The ESB has tonight called for urgent action to head off a shortage of electricity over the next five years.
The power network said there was an estimated shortfall of 750 megawatts between now and 2007.
The company's generation adequacy report pointed out that there were no plans to build any new generating capacity, a process which would take at least two years.
It said the capacity shortfall was expected despite a slowing-down in the growth in demand for electricity from 4.6 per cent in 2001 to an estimated 3.5 per cent over the next few years.
"Given that it will take two to three years to commission new large-scale generation plant, immediate action is required," the report said.
ESB managing director Mr Kieran O'Brien said: "It is evident that the current market arrangements are not attracting sufficient new investment in generation."
"While the Commission for Energy Regulation is taking action on redressing this, there is still some concern in relation to supply in the short term.
He said: "As a result of deregulation in the industry, it is the market that will ultimately dictate the actual amount of generation that is constructed, and it is therefore imperative that sufficient incentives are provided to attract new generation into the industry and to ensure continuity of supply."