Glasgow could be hit by further industrial action amid an ongoing £500m equal pay dispute.
Trade unions have accused Glasgow City Council of “broken promises” and say the local authority is reneging on previous commitments given to predominantly female claimants.
Unite confirmed on Monday that its members are now to be balloted for industrial action.
Sharon Graham, general secretary of Unite, said: “It’s a scandal that thousands of workers are still awaiting cash that should have been in their pockets months ago.
“Instead, the claimants continue to face unnecessary delays in getting what is owed to them. Let’s remember that this situation was entirely of Glasgow City Council’s making through an unfair and discriminatory pay grade system.
“Unite’s members have the full support of their union in challenging the Council to get the cash they are owed without any further delay.”
Unite members being balloted include clerical and administrative workers, caterers, home carers, cleaners, janitors, car park attendants and education service workers.
The authority part-settled with thousands of women at a cost of £505m in 2019.
But the union said, despite progress being made, around 5000 claimants have had no settlement for the period up to March 2018, and around 18,000 are still waiting for a settlement for the period after March 2018.
Wendy Dunsmore, Unite industrial officer, added: “Glasgow City Council’s broken promises over the payments to claimants, who are predominantly female, is disgraceful. Thousands of claimants are being told that they may have to wait several years before they get their settlements.
“Many received an interim payment up to 2018 and they should so again. It’s an unacceptable situation and that’s why we are holding a ballot for industrial action. Many of these workers don’t have the time to wait months and years for their money.
“There is a cost of living crisis with inflation soaring. Choices are literally being made every day by families over the cost of fuel, energy and living.”
The delay in making payments is being blamed on a new pay and grading system, which will not be fully implemented until 2024.
A spokesman for Glasgow City Council said: “We are following the process agreed with unions at the time of the 2019 deal.
“We have made it clear we are ready to make offers on new claims – and are committed to discussing the gap period thereafter.”
The ballot on industrial action will open on February 28 and is set to close on March 14.
If the ballot is successful then Unite’s members involved in the dispute could take strike action from the end of March onwards.