The Civil and Public Services Union, which represents 13,000 lower paid civil servants, has decided to escalate its industrial action in protest at the Government's pay cuts.
The union is already participating in the public service work-to-rule, which involves thousands of staff in the civil service, as well as the health, education and local government sectors.
Up to now staff have withdrawn cooperation and refused to answer phones in different regions for up to half-a-day at a time.
However, following a meeting of the strike committee today, they have instructed members that they should only do their own work.
There will also be an escalation in episodes of disruption, but the union will not announce in advance where or when escalations will take place.
The union is currently balloting members for full strike action. The ballot result is expected at the end of the month.
Earlier today, 70,000 public sector employees belonging to the country's largest union SIPTU joined the public sector work-to-rule.
SIPTU President Jack O'Connor has warned that there could not be a resolution to the dispute unless the cuts were reversed.
Labour Relations Commission Chief Executive Kieran Mulvey is to meet with the leaders of the public services committee of the Irish Congress of Trade Unions later this week.
Speaking on RTÉ's Morning Ireland, Mr Mulvey, who has offered himself as a mediator, said previous suggestions of reform by the unions could form the basis of a future agreement.