Members of the GMB and Unite unions in Scotland have voted to reject a pay offer to council workers.
The proposed 2% increase with a guaranteed £800 rise for lower earners was rejected by 93% of GMB members and 83.3% from Unite who took part in their ballots.
The unions said the votes increased the prospect of strike action this summer.
Local authority body Cosla said the offer remained on the table while negotiations continued.
The GMB, which represents 20,000 local government workers in services such as home care, refuse, school support, and roads and maintenance, is calling for a "significantly improved offer".
The current offer would give those earning up to £25,000 an increase of 2% or £800, whichever was greater, while those in the £25,000 to £40,000 band would receive 2% and those earning up to £80,000 a year would get 1%.
GMB Scotland senior organiser Drew Duffy said: "It's been a wretched year and a desperate decade for council workers, especially the lowest paid and the services they deliver.
"Home carers, refuse workers, and school support staff have got on with the job for all of us despite being failed on PPE, testing and safe working guidelines. Furthermore, they did this after years of political austerity, which cut their pay in real-terms and gutted their services."
Unite has previously described the offer as a "slap in the face rather than a clap for local government workers".
Its Scottish secretary Pat Rafferty said: "There is palpable anger that local government has become the forgotten section of our public services, particularly after a year of the pandemic.
"This should be a wake-up call to Cosla and the Scottish government to get back to the negotiating table with an improved offer, which properly values and rewards the workforce who have gone above and beyond the call of duty."
A spokesman for the local government body Cosla said on Wednesday: "We have made an offer to our trade union colleagues. This offer remains on the table whilst we continue with on-going constructive negotiations."