Postal services will face serious disruption from Monday in spite of continuing efforts to avert industrial action by workers in An Post.
A ban on overtime working and an all-out strike at the GPO in Dublin will take effect from midnight tomorrow, the Communications Workers' Union announced.
There will also be strikes at "selected locations" around the country, the union said.
An Post condemned the union's decision to go ahead with the action while talks with the National Implementation Body (NIB) were ongoing at Government Buildings. The talks adjourned shortly after 9.30pm and will resume today.
It said a ban on overtime would cause severe disruption to mail deliveries, as the system had become dependent on overtime to function normally.
The NIB, the partnership watchdog body which comprises representatives of the Government, unions and employers, was continuing to hold meetings with the two sides last night.
However, CWU general secretary Steve Fitzpatrick, who left the talks to announce details of the industrial action, said little progress was being made.
"I don't want to mislead anybody. I didn't see any indication that we were doing anything other than exploring possibilities," he said.
While mail deliveries will be disrupted, the union pledged that social welfare recipients would not be affected by the dispute.
Mr Fitzpatrick said "all necessary steps" would be taken to ensure that welfare and pension payments were not interrupted. "In all disputes in the past we have managed to ensure that all such payments were made."
This meant the GPO would remain open, but solely for the purpose of maintaining payments to welfare and pension recipients, he said. A spokeswoman for An Post, however, claimed the union's stance on this issue was already causing considerable confusion.
There was more to maintaining welfare payments than keeping the relevant counters open, she said, as there were also backroom operations and security issues to be taken into account.
An Post was unable to say precisely what effect the industrial action would have as the union had not communicated its intentions in detail, she added.
The Irish Charities Postal Users' Forum said any disruption to the service would have a "devastating impact" on fundraising campaigns. The business group Isme said the "selfish strike" could "put many businesses to the wall".
The strike is over the company's failure to pay the full terms of Sustaining Progress to the CWU's 8,500 members.
An Post accepted a Labour Court recommendation in July - drafted by a technical group including industrial relations troubleshooter Phil Flynn - that the increases be paid provided postal workers agreed to a range of work practice changes.
The CWU says the two issues should not be linked. It says members are entitled to the cost-of-living increases agreed under Sustaining Progress without having to change work practices.
It also wants the company to immediately pay increases due its pensioners, who are caught up in the dispute as their pay rises are linked to those received by staff.
Mr Fitzpatrick said the company should show the "same regard" for its pensioners as the union was prepared to show for welfare recipients generally. He said the union had chosen a nationwide overtime ban as its "initial course of action" in order to highlight the company's reliance on overtime to keep the postal service operating.
A central aim of the work practice changes being sought by the company in its collection and delivery operation is to reduce its dependency on overtime.
With overtime payments included, some top-earning postal workers can earn up to €70,000 a year. A CWU spokeswoman said this figure was not typical, however. Most postmen and women earn basic salaries of between €20,000 and €25,000, before overtime payments are added.
The CWU says some aspects of the Labour Court's recommendation in July are unacceptable. These include reductions in holiday pay and changes to leave entitlements.
