More than 90,000 council staff are to be balloted for strike action after their biggest union voted against a pay offer from Cosla.
Unison said the local authority body decided to “impose an insufficient pay award” despite its workers voting against it.
Cosla said the current offer is fair and was accepted by both GMB and Unite.
The current deal from COSLA includes an hourly increase of 67p (or 3.6%), whichever is higher.
It will apply to nearly all council staff except teachers.
The union said the pay award fell short of “expectations given the 25% real-terms pay cut over the past 14 years”.
Unison already has a mandate for strike action for waste, recycling and street cleaning workers in more than a dozen councils.
David O’Connor, the union’s local government lead, said COSLA’s decision to go ahead with the pay offer despite it being rejected by workers was “upsetting and infuriating”.
“To say this is a bitter disappointment is an understatement,” he said.
“Just two days ago, COSLA’s lead negotiator councillor Katie Hagman and the cabinet secretary for local government and finance Shona Robinson MSP assured the union they were committed to a negotiated settlement.
“Now, they’ve resorted to some of the worst employment practices by imposing this deal. They should be utterly ashamed of themselves.”
COSLA said the deal was “fair, above inflation and strong settlement” that has already been accepted by the the two other unions involved in the pay talks.
Hagmann said: “COSLA highly values each member of our important workforce and their vital work serving Scotland’s communities every single day.
“It is at the absolute limit of affordability in the extremely challenging financial context we face.”
The councillor said the offer doesn’t mean an end to negotiations and added that COSLA will continue dialogue with trade unions “with the ambition reach a collective agreement if at all possible.”
Finance secretary Shona Robison said: “The decision made by council leaders to implement the local government pay offer will halt any further delays and get pay in the pockets of valued workers – including those who need it most – before Christmas.
“The pay award will see the lowest paid workers receive a 5.63% pay increase and most local government workers receive more than 4%.
“Although the Scottish Government has no formal role in these negotiations, we have provided £77.5m to support this offer which Unite and GMB members overwhelmingly voted to accept. I hope that Unison members recognise the strength of this offer.
“I confirmed to COSLA and unions when we met that the Scottish Government has utilised all available funding to support local government pay.”
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