An Post is set to close 161 post offices around the country.
The move is part of its transformation programme, and a €50m investment in the network.
It says 161 postmasters have applied for it's voluntary retirement package.
A full list of post office closures is to be issued at the end of the month.
An Post says the company, the Irish Postmasters Union (IPU) and postmasters are "in agreement" that the consolidation of the network, and subsequent transfer of business to neighbouring offices, is "essential to the sustainability of the overall network".
It adds that mail delivery and collection services are not affected.
In statement, An Post says it "reaffirms its commitment that communities of over 500 people will have a post office and that over 95% of the population will be within 15km of at least one post office."