An Post has said it is putting in place emergency plans in the event of a postal strike, but said the refusal of the main trade union to provide any information on the nature and timing of the action had made this "extremely difficult".
In a statement this evening, An Post said its demand that the Communications Workers' Union lift its ban on the hiring of casual staff in Dublin had been refused by the union's leadership.
The company said the union had also "refused to give any details of the type, location or duration of the industrial action being planned for the coming days".
"The CWU refusal to provide any information on the nature and timing of the action makes it extremely difficult for An Post to advise customers or to put in place arrangements to minimise the impact of that action," An Post said.
"There is a strong possibility that all mail - including Swift Post and EMS services - may be subject to delay from Friday onwards, when the period of strike notice concludes."
It said the hiring of casual staff in Dublin would greatly alleviate the service difficulties arising from what it said were "sick absence" levels reaching 10 per cent on certain days in Dublin.
"It is completely unacceptable that the CWU should attempt to hold the company and State to ransom by refusing to engage meaningfully and honestly on the subject of change, choosing instead this destructive, outdated and utterly inappropriate route of industrial action and service disruption," An Post said.
The company said it was "putting in place all possible contingencies available to the company in an effort to minimise the level of disruption to customers".
The CWU issued strike notice over the company's failure to pay wage increases to its members under the Sustaining Progress agreement.
An Post had
wanted to tie the pay rises to changes in work practices.