Minister for Communications Noel Dempsey was called on yesterday to intervene after An Post outsourced 30 jobs in response to industrial action by staff on Monday.
Staff who returned to work at the company's customer services section at the GPO in Dublin following the removal of pickets were told their jobs had been outsourced to a call centre in Clonakilty, Co Cork. They remained on the payroll yesterday but had only minimal duties.
The company's action sparked a new row with the Communications Workers' Union, which organised Monday's 18-hour action in pursuit of a pay claim.
It called off the industrial action at the request of the National Implementation Body (NIB), which is this week overseeing an independent examination of costs in dispute between the two sides.
An Post said it had outsourced the customer services jobs because the CWU had broken a "no-strike" agreement in relation to the staff concerned, signed in 1999. A spokeswoman said that in line with this agreement, customer service staff had worked normally during the one-day stoppage by postal workers last December.
However, on Monday the staff had left their posts to participate in the strike. As the company was getting thousands of calls from members of the public that day, it had had no option but to outsource the service.
An Post had asked for a meeting with the CWU to seek assurances there would be no repeat of the action by customer service staff, but was still awaiting a response, she said.
The CWU, however, said the company was "in clear breach" of an NIB recommendation that the parties refrain from industrial action pending completion of the costings exercise now in place.
CWU national officer Seán McDonagh said the union had written to Irish Congress of Trade Unions general secretary David Begg about the matter.
Mr Begg said last night he had raised the issue with both Mr Dempsey and the chairman of the NIB, Dermot McCarthy.
