Up to 150 postmasters have staged a protest outside Enda Kenny's constituency office in Castlebar, Co Mayo.
An Post is considering the closure of up to 600 post offices in order to stem losses of up to E12m a year.
However, a Government-sanctioned report by businessman Bobby Kerr has recommended closing 80 offices - and streamlining products and services.
Sean Martin of the Irish Postmasters' Union told Mid West Radio that his organisation is frustrated at the Taoiseach's in-action on the issue.
“At the end of the day, the Taoiseach is the person that’s responsible to deliver policy and to deliver local services to local communities- and he has reneged on his decision to have a vibrant post office reaching into most communities in Ireland.”