The Dail was told about "red alert" and "amber alert" warnings of electricity shortfalls in the ESB's supplies, but the Minister for Public Enterprise insisted that there was "sufficient capacity to meet our winter electricity needs".

Ms O'Rourke said, however, the five-month delay by An Bord Pleanala in giving a decision on applications by the ESB and another company, Viridian, to build new electricity plants was "leading to fears and worries".

"An Bord Pleanala is independent body and it has a job to do. I do not want to comment on its decisions. The only comment I will make is that this is a matter of national interest and it has deferred its decisions on these applications for five months," said Ms O'Rourke.

The issue was raised by Mr Emmet Stagg, Labour's energy spokesman, who asked about the "serious imminent risk of power cuts". He said that "amber alerts are now a regular occurrence" and a number of red alerts had occurred. "When a red alert occurs, we are near to a close down of a whole section. Machinery in factories that require full load trip out and stop production, and that has already occurred."

Ms O'Rourke said on Tuesday at a regular meeting with the ESB chairman, she raised the issue of alerts. The chairman "made it clear that the company's capacity of 4,485 megawatts is sufficient to meet winter electricity needs and the winter demand will be 3,700 megawatts".

The Minister explained that continuing growth in the economy had led to an "unprecedented demand for electricity. This increase in demand means that new generation capacity, beyond that which is already under construction, will be required by 2001."

The ESB and others had projects in the pipeline and she added that because of the economy's growing need as well as the introduction of competition in the electricity market, it was important that new generating capacity was brought on stream at an early date.

However, no further movement could take place in constructing new plants until the planning processes were completed.

Mr Stagg put it that the electricity supply was "very vulnerable" and said the State was now dependent on the interconnector between the Republic and Northern Ireland to ensure a continuous supply. That was a vulnerable source of supply because it had been blown up regularly by the IRA and "the IRA could start blowing it up again at any time".

He asked the Minister to agree that "she was wrong earlier in the year in refusing to give authority to the ESB top proceed with its planning and with the development of further capacity". Ms O'Rourke replied that the ESB had been given the go-ahead to apply for planning, but it could not proceed until it got a decision on its planning application.