Taoiseach Bertie Ahern has criticised tomorrow's proposed strike action by more than 1,000 ESB technicians.
"There's no need for industrial action at all in this case. They should try and take a step back and ease the situation," he said. "It is entirely unnecessary, unhelpful to the workers themselves, to the organisation they work for and to the general public."
Power supplies will not be immediately threatened by the action, but a prolonged strike could lead to blackouts.
The network technicians are in dispute over the extent to which outside contractors are involved in the delivery of a €3.6 billion programme to upgrade and modernise the network.
Paul Friel, ATGWU strike committee
Paul Friel of the ATGWU strike committee said this afternoon they had been excluded from a meeting due to take place yesterday with management and that therefore members had no option but to proceed with the strike, effective from tomorrow.
Two other unions - the TEEU and Siptu - have expressed concern about the action though they are also in talks with management about the outsourcing proposals.
They issued a joint statement today saying they would engage in a series of meetings with management to resolve outstanding issues and would also meet the ATGWU tomorrow to discuss the potnetial for a unified approach.
The TEEU and Siptu said their members should report for work tomorrow but should not carry out work normally done by ATGWU members.
Mr Friel said the ATGWU had received written confirmation that the other unions had not objected to their attendance at the meeting and said that at every stage of the dispute the union had made it clear they were open to talks at any time.
"At this point there are no offers of talks from ESB, and in order to uphold the mandate of our members we have no option but to take official strike action," he said.
ESB management said over the weekend it would not enter talks with unions unless all strike threats are withdrawn. The spokesperson had said that while it welcomed the withdrawal of a strike threat planned for today, the spokesperson said the ball was now "in the ATGWU's court".
Questioning the ESB's insistence that unions adhere to agreed negotiation structures, Michael O'Reilly, Regional Secretary of the ATGWU said the dispute could be resolved through negotiation.
About 1,700 external contractors are at present employed by ESB Networks alongside some 2,200 staff technicians, more than half of whom are represented by the ATGWU.
The ESB has refused to comment until it receives official notification of the strike from the ATGWU.