The Irish Postmasters' Union (IPU) says it fears for the future of 1,400 sub post offices if the majority of social welfare payments are paid directly into recipients bank accounts.
IPU General Secretary John Kane said: "The single biggest customer [for sub post offices] is the Department of Social and Family Affairs, which accounts for upwards of 60 per cent of turnover. This business is now under threat by the department's use of the Electronic Funds Transfer (EFT) facility to the bank."
He added: "The union wants want to see choice being left with the social welfare recipient as to how they receive their payments, including the current range of payment methods."
IPU representatives have presented Minister for Social and Family Affairs Seamus Brennan with some of the 500,000 postcards, signed by the public, calling for welfare payments to be remain accessible at the post office.
Mr Kane welcomed the commitment of Mr Brennan to give An Post time to organise its own EFT facility.
"The availability of an EFT facility at the post office will not be as straightforward as it might first appear," said Mr Kane. "The post offices would not wish to see social welfare recipients charged for accessing their money at a post office, as currently happens at the bank," he added.
Current bank charges mean that social welfare recipients could pay as much as €50 a year to keep an account and access their payments.
The union called on Minister for Communcations Noel Dempsey to use his influence with An Post to ensure a timely provision of this EFT facility.
Meanwhile, it emereged today that An Post is seeking a rise in the price of stamps from 48 cent to close to 60 cent.