Postal services are expected to return to normal in most areas today following yesterday's unofficial strike which left thousands of social welfare claimants without payments.
Continued disruption of services is expected, however, in parts of Cork, where mail deliveries as well as welfare payments have been disrupted.
Yesterday's action by counter staff resulted in the closure of the GPO in Dublin as well as 10 other post offices and three sub-post offices in the capital.
Post offices in Cork city; Macroom, Youghal and Cobh in Co Cork; Limerick city; Shannon, Co Clare; Castleblayney, Co Monaghan; and Ballinrobe, Co Mayo, were also closed.
An Post estimated that 10,000 unemployment benefit or assistance claimants were unable to collect payments due yesterday because of the dispute.
The strike, by members of the Communications Workers' Union (CWU), relates to a year-old agreement between the union and the company.
As part of the deal, staff received a 12.5 per cent pay increase in return for co-operating with An Post's plan to convert some 50 company-owned post offices into privately-run sub-offices.
Both sides claimed yesterday that the other was acting in breach of this agreement.
The CWU said An Post was obliged to consult with it on the conversion of individual offices, but had failed to do so last week in relation to the post office in Midleton, Co Cork.
Mr Con Scanlon, the union's general secretary, said An Post has promised to put proposals to the union regarding Midleton but "we didn't get them".
Instead, he said, An Post had attempted to proceed with the change without consultation, which had implications for the four clerks and 14 delivery staff based at that post office.
A spokesman for An Post, Mr John Foley, said two of the conversions to sub post-offices, at Carrickmacross and The Curragh, had already taken place. Midleton was next on the list and the company had discussed the changes at local level and outlined the options open to staff.
He said staff at Midleton had been "perfectly happy" with the outcome, but unofficial action was taken by workers at other post offices in the county, which closed as a result on Friday.
Apart from three in Dublin, sub-post offices remained open yesterday so most social welfare claimants were able to collect payments by travelling to their nearest sub-office.
Unemployment benefit and assistance claimants who use swipe cards, however, can claim at designated post offices only, so were unable to receive payments.
Those outside the Cork area will be able to collect their payments today.
Postal deliveries were not affected except those in the Midleton area, and further disruption is anticipated today.
The Irish National Organisation of the Unemployed expressed concern that social welfare claimants might not be able to receive payments. Any delays, it said, could cause hardship.
No talks between the company and the CWU had been arranged yesterday.