Industrial action at Newry, Mourne and Down District Council (NMD) will extend into next week as confidential negotiations have failed to reach an agreement.
Members of GMB, NIPSA, and SIPTU took action from April 10 with Unite joining the work to rule from April 12.
The local authority employees claim NMDDC management has reneged on a commitment to a partnership-based job evaluation process.
The council and the four unions held talks with the Labour Relations Agency on Monday, however further talks are now required ahead of the bank holiday weekend.
A NMD spokesperson said: “Newry, Mourne and Down District Council can confirm that Management Side met with the Joint Trade Union Side on Monday, April 24, for further talks under the auspices of the Labour Relations Agency.
“Joint talks will continue this Friday.”
The union work to rule action has resulted in a significant impact to council services including those at leisure centres and domestic waste and recycle bins not emptied for three weeks.