The ESB has described questions raised about the way in which it accounted for pension scheme liabilities in its accounts as "misleading" and "inaccurate".
The company has also distanced itself from the management position on the scheme expressed in emails between top managers in 2011 revealed this weekend by RTÉ.
In those emails, the managers discussed requests by auditors KPMG for assurances that the ESB group of unions was in broad agreement with the ESB on the changes in accounting treatment for the pension scheme in its accounts.
The emails also revealed that managers were aware of the opposition of the group of unions.
They expressed concern that any public statement of that opposition by the group of unions would hamper the change in accountancy treatment.
One executive writes: "...should Brendan [Ogle - Secretary of the Group of Unions] decide that he does not agree with the wording and send something to us in writing, it would unavoidably force us to change the accounting treatment and all that entails".
This evening an ESB spokesperson described those emails as "incorrect" - and issued a statement outlining the company's current stance on the issue.
The spokesperson said that what KPMG had been seeking were assurances that the company would not be putting any additional contributions into the scheme in the event of a future deficit.
The company's position was and is that it will not be injecting additional contributions into the scheme beyond its existing contributions "under any circumstances".
Unions are currently balloting for industrial action in a row over the pension scheme deficit of €1.6bn and have mounted a legal action over the company's decision to pay dividends to the State while that deficit remains outstanding.
The ESB Group of Unions believes that because the scheme is a so-called defined benefit scheme, the company should take responsibility for ensuring that pension benefits are delivered to staff in future years, and should contribute to any deficit that may arise.
However, the company insists that it has no responsibility for funding future deficits, and that it has correctly accounted for the scheme as a defined contribution scheme.
In this evening's statement, ESB said there was "significant misunderstanding" of how the ESB accounts for the DB scheme in its financial statements.
The statement outlines steps taken in 2010 to address the then deficit of €2bn, adding that the scheme's actuary had confirmed that the 2010 proposals achieved that aim.
It says that following that agreement, it initiated a review with its advisors as to the appropriate accounting standard.
It believed that because the ESB defined-benefit scheme was not a "balance of cost" scheme, it was decided to account for it as a defined-contribution scheme - whereby the full amount of any pension scheme deficit was not placed on the ESB balance sheet.
It says that ESB is not liable for the full amount of any deficit which may arise, and that treating it as a defined-benefit scheme would not have been appropriate.
It says that ESB did not therefore place a liability on its balance sheet that did not properly belong there.
ESB also states that the Trustees submitted a proposal in 2012 to the Pensions Board to meet the regulatory Minimum Funding Standard by the end of 2018.
The company says that proposal was approved and is on track to meet the 2018 target.
The statement notes that the ESB does not envisage winding up its scheme.
It also notes that the auditors of the financial statements in 2010, 2011 and 2012 had expressed unqualified opinions that they were a true and fair view of the ESB's affairs.
The statement says: "It remains ESB's view that the defined contribution accounting treatment adopted by the company in 2010 correctly reflects ESB's obligations to the scheme."
ESB says that it did not seek the agreement of the ESB Group of Unions to the change in accounting treatment, nor did ESB or the company's auditors require the unions to agree to the change in accounting treatment.
ESB says it is fully satisfied that all its dealings with its auditors have been and continue to be fully truthful and accurate and rejects in the strongest possible terms any allegations to the contrary.
It says that the change in accounting treatment did not change the nature of the scheme itself.
It also rejects reports that it had changed the scheme from a defined benefit to a defined contribution scheme, or that the change in accounting treatment shifted the contingent liabilities of the scheme from ESB to the employees.
The company also reiterated that it will fully defend the law suit by four employees in the High Court.
Meanwhile, the secretary of the ESB group of unions has said that it will respond fully to the ESB statement in the coming days.
He said that the statement gives no clarity to ESB workers as to how the company is going to meet its responsibility for the workers pensions.
The ESB Group of Unions note that the ESB is distancing itself from its own very senior management positions as captured on RTÉ RADIO's This Week programme last Sunday.
The group of unions note that the ESB statement does not repeat the assurances of the former Chief Executive Padraig McManus who wrote to every ESB worker in the summer of 2010, reassuring them of their pension rights and the companies position regarding those rights.