Unite the union confirmed it will recommend its local government membership reject the revised pay offer from COSLA.
Following a meeting of local government representatives in Glasgow, the union will now hold a consultative ballot of members in the next few weeks.
The final revised pay offer was made on Friday by COSLA offering a three per cent pay increase for all local government workers earning up to £80,000, rather than the previous threshold of £36,500.
Charlie Macdonald, the vice-chairman of Unite Scotland’s Local Authority committee, said: “Unite has firmly taken the decision to reject the revised offer by COSLA because in reality it actually means the lowest paid workers in local authorities across Scotland will be in an even worse situation.
“COSLA should be doing far more to address the issue of low pay not making it comparatively worse, while also addressing a fair pay award for the whole local authority workforce.”
Last week GMB Scotland senior organiser Drew Duffy echoed similar sentiments.
He said: “Cosla’s leaders have ignored the voices of the lowest paid in local government.
“This revised offer does nothing to help staff like home carers, refuse workers and school cleaners.
“Instead the biggest cash rises will go to the middle and highest earners, and not those on the lowest grades who have suffered the most after 10 years of austerity.
“Cosla has got its priorities all wrong and GMB will be strongly recommending our 30,000 members across local government reject this unfair and unequal pay offer.”
In reponse to the GMB criticism Cosla’s resources spokeswoman Councillor Gail MacGregor said: “Cosla’s policy on pay parity across the workforce means that we have to be fair to all of our workforce.
“That is why the same improved offer has been made to all four of the bargaining groups we are in discussions with.”
Mr MacDonald questioned Cosla’s supposed desire to install parity.
He said: “It’s bizarre for COSLA to talk about parity of pay while offering those over £80,000 a flat rate offer of £1600.
“Yet, the reality for some of our poorest paid members is that they are being offered barely more than seven pounds per week more against the backdrop of ten years of austerity.
“This is simply unacceptable, in the end our members will make a democratic decision but Unite will be balloting them to recommend rejection.”