A planned strike by ESB workers has been called off, but both sides now differ on the effect of their Labour Relations Commission agreement.
The row centred on a €1.6bn deficit in the company's pension fund and the decision to withdraw notice of strike action came after talks between management and unions over the weekend.
ESB has said there will be no effect on the company's balance sheet as a result of the settlement, but unions say that is not the case.
The ESB claimed in a statement that the deal said no liabilities would be added to their balance sheet and that dividends would continue to be paid to the Government.
However, the leader of the ESB group of unions Brendan Ogle believes that the treatment of the company pension scheme as a defined benefit scheme would add at least €369m to the balance sheet.
The strike, which was due to take place next week, would have caused blackouts in homes and businesses across the country.
Unions withdrew the strike threat after claiming it had secured protections for the pension scheme.
A statement on behalf of the unions involved in the negotiations said staff had been subjected to unfair public criticism during the dispute.
"The ESB workers have been publicly vilified for nothing more than protecting themselves and their families against an attempted destruction of their bought and paid for pension rights," it claimed.