Postal deliveries to rural areas are facing a fifth day of delays and in a pay dispute between the Irish Postmasters' Union (IPU) and An Post.
More than 600 members of the IPU contracted to run rural post offices are refusing to accept deliveries until 8 a.m. - two hours later then usual. They are also refusing to supervise and assist mail-sorting.
This is leading to delays of up to two hours for deliveries to some areas, although An Post denies there is a backlog of undelivered post.
The dispute centres on conditions and pay for the contracted postmasters.
The IPU is looking for a €40 per hour increase for sorting duties and for post offices opening before 8 a.m. Up to now, postmasters have been paid €2 an hour for supervising and assisting with mail-sorting.
But An Post said postmasters have already received pay increases over the past five years.