Talks about the future of An Post between management and the Communications Workers' Union (CWU) ended last night without agreement and are expected to continue this morning at the Labour Relations Commission (LRC) in Dublin.
At issue yesterday was An Post's proposals to manage the additional mail as a result of the two-week strike by hiring an additional 200 casual workers to help clear the backlog of mail.
Despite three meetings on the matter yesterday, no agreement was reached.
According to a spokesman for An Post, the company's service recovery plan is designed to return services to normal in "as short a time possible as well as in the most cost-effective manner".
The spokesman said if agreement on this issue, which he described as a "matter of urgency", is not reached tomorrow morning "it is our intention to move as quickly as possible to the Labour Court.
"We don't have time to bandy words about. We need to resolve this issue as soon as possible," he added.
Mr Seán McDonagh, a national officer with the CWU, last night accused An Post management of trying to "derail" the national talks brokered by the LRC by "reneging on all established agreements and by imposing a new delivery regime which will effectively delay full restoration of the delivery service until April 26th at the earliest".
He said he remained committed to the national talks under the LRC.
He added that he would not be "bullied into accepting a crazy new postal delivery regime that would further tarnish the reputation of the system and damage the business in the long term".