Delays in postal deliveries to rural areas are expected on Monday when sub-post office owners begin industrial action.
Members of the Irish Postmasters' Union (IPU) say they will not accept mail deliveries from central locations until 8 a.m. in pursuit of their claim for a pay increase.
They will also not be opening their premises until 8 a.m., about two hours later than normal.
A spokesman for An Post said there was no prospect of further talks over the weekend, following a breakdown in negotiations between the company and the union on Thursday.
The impact of the action would not become clear until mid-morning on Monday, he said, but delays in deliveries of up to two hours could be expected.
Rural areas only would be affected, he stressed.
About 600 postmasters and postmistresses, who work for An Post as subcontractors, are involved in the dispute.
They claim allowances for early-morning work are insufficient and they are not being paid enough for carrying out a number of functions.
An Post has pointed out that the contractors received pay increases of 37 per cent in 1997, 6 per cent in September 2000 and 12 per cent in January 2001.
In addition, they would be receiving a 15 per cent increase in October, backdated to September 2000.
They had also been paid all phases of the Programme for Prosperity and Fairness,
The IPU acknowledges that pay has been substantially increased in recent years, but says its members are still paid poorly for the service they provide.
The spokesman for An Post said the question of taking action against IPU members for breach of contract was "something that will be looked at". However, no decision of that nature had been taken to date.
