Postmasters say the failure to adopt an action plan for post offices will threaten rural communities.
The Irish Postmasters Union (IPU) is before an Oireachtas Committee today to discuss its concerns over the future of the network.
They say that despite awarding the contract for social welfare payments to An Post the Government is driving people to use their bank accounts to receive benefits.
IPU General Secretary Brian McGann says TDs must vote for an action plan to support post offices tonight or they will damage rural communities.
"What's going to happen after tonight, if the postmasters' motion is lost we won't just be talking about the sustainability of a network - we will be talking about the sustainability of communities in this country," he said.
"This will become a much, much bigger issue."