Renewed attempts to resolve the postal dispute are expected to take place today, but there is still no sign that the parties are ready to begin talks.
Deliveries to the areas affected, which include Dublin and neighbouring counties, had slowed to a trickle yesterday as the dispute began to bite.
Charities were among those suffering most as a dramatic drop in donations by post began to affect revenue.
The dispute began at the weekend when An Post began suspending staff at its Dublin Mail Centre in Clondalkin for refusing to carry out management instructions.
By yesterday, 553 employees had been taken off the payroll at the centre, in addition to 89 casual staff in delivery offices whose contracts were suspended because the company had no work for them.
The Minister for Communications, Mr Ahern, yesterday urged the company and the Communications Workers' Union to maintain contact with the Labour Relations Commission.
The two parties attended separate talks with the LRC on Wednesday but were unable to agree a basis on which direct discussions might begin.
Mr Seán McDonagh of the CWU said the most important issue for the union was that the suspended staff be reinstated and the postal service restored before talks could begin. He said this was not a precondition but it did not make sense to begin negotiations on substantial change at the company while hundreds of staff were off the payroll.
A spokesman for An Post said it wanted the union to deliver on work changes that had already been paid for and to resume negotiations on a recovery plan, which it had walked out of before Christmas.
The LRC is expected to renew contact with the parties today.
Mr McDonagh also accused the company of trying to provoke an escalation of the dispute by offering overtime to staff remaining in the delivery offices where colleagues had been laid off.
The An Post spokesman said the overtime had been offered to staff on a different grade from those who had been laid off, and there was no question of trying to provoke a response.
Mr Tom Arnold, chief executive of Concern, said donations to the agency were substantially down because of the dispute and he believed other charities were also likely to be hit, particularly those running appeals at the moment.
A prolonged dispute, he said, could have "serious consequences".
The Civil and Public Services Union, the second largest in An Post after the CWU, issued a statement calling for renewed talks and criticising management for its "unwarranted" actions in the dispute.
