Workers in the GMB union at Swansea council began a strike ballot this week over a single status pay deal.
Jeff Burns, GMB organiser, said, “The council would soon take action if their staff, as citizens of Swansea were withholding council tax.
“Our members say they are fed up.
“The council has refused to admit liability for nearly 500 equal pay claims lodged with the Employment Tribunal by the GMB’s solicitors.”
The ballot closes on 3 December.
Birmingham council workers have received the letters outlining the imposed single status pay contracts.
At least 4,000 workers will have pay reduced, with some receiving pay cuts of up £17,000. Last week 1,500 workers protested against the plans.
All the unions in the council are preparing strike ballots.