The Minister for Communications has warned that the financial crisis facing An Post will have to be confronted.
Mr Ahern said the facts were that the company was losing €600,000 a week, or €2.5 million monthly.
"This is the stark reality that all sides have to address. To do otherwise is to walk away from responsibilities not just to the taxpayers, who own the company, but to the employees who work for it and the customers who rely on it."
Between 2002 and the end of this year, An Post would have lost €100 million, he added.
"Its cash reserves are almost exhausted. They have only a finite amount of family silver to sell to keep afloat. And the economy and the public cannot afford to bear continuing price rises to sustain the existing cost structures of the company."
Mr Ahern, who was replying to a series of special notice questions, said An Post must return to profitability.
"The company has to change. And time is not on its side." Earlier, the Tánaiste, Ms Harney, appealed to both sides to resolve the dispute in today's talks with the Labour Relations Commission. She was replying to the Fine Gael leader, Mr Enda Kenny, who said there were draft codes of practice for disputes in essential services.
Ms Harney said there was a code of practice. "It's important, in that context, that parties who have signed codes of practice honour them."
She urged employees to return to work to implement the plans they had signed on for.
