Over 200 postal workers around the country are sorting mail in their homes this morning after sorting offices were closed during an industrial dispute by postmasters.
Another 800 workers are travelling to central offices to sort mail themselves.
The Irish Postmasters' Union (IPU), which represents 540 rural postmasters and postmistresses, are closing down rural sorting offices each Monday and Friday, starting from today, in an escalation of their pay claim against the company.
The Communications Workers' Union (CWU), which represents post workers, had agreed the arrangement with An Post.
An Post has rejected claims the action is illegal or a security risk, claiming it had no option if it wanted to avoid massive disruption to deliveries.
A spokesman said that because of the contingency arrangements, it expected little to no disruption to deliveries.