As many as 17,000 Birmingham City Council workers could strike over plans to switch their pay from weekly to monthly.
Officials from the Unite union are balloting for industrial action after claiming that council bosses are refusing to negotiate.
The changes, which will cut the cost of paying wages, are part of a controversial pay and grading review imposed on staff earlier in the year.
Union leaders say thousands of low-paid mainly women workers, including cleaners, classroom assistants and dinner ladies, will be out of pocket when the new system is introduced next month.
A spokesman said employees used to being paid weekly would struggle to buy Christmas presents if they had to wait until the end of November before receiving any money.
But cabinet member for equalities and human resources Alan Rudge hit back, pointing out that he had offered loans to tide over anyone who was struggling financially as a result of the change.
All staff switching to monthly pay would be offered an additional month’s money in a lump sum.
Repayments would not have to be made until February 2009, and then in six monthly instalments.
He said a more generous offer, allowing repayments to be deferred until an employee left the council, had been withdrawn following the failure of the union to accept it.
Proposals for a loan were first put forward by Coun Rudge (Con Sutton Vesey) in the summer, but are yet to be approved by Unite.
Relations between the two sides have been further soured by union claims that the council is paying consultants working on its business transformation project £900 per day plus hotel expenses. Unite said it was appalled at the difference in the treatment of consultants and low-paid staff.
Coun Rudge told a full council meeting that he was prepared to meet the union at any time.
He accused the union of breaking a verbal promise to accept the offer of loans.
“I was under the impression they had agreed, but subsequently they spoke against what they had agreed.”
After the meeting Coun Rudge said he could hardly believe the union was balloting for industrial action over a relatively minor issue.
The pay and grading review had delivered the best conditions for staff for 20 years, he insisted.
Coun Rudge added: “We have increased basic pay and we have awarded back pay.
“They can’t expect to take all the things we offer them and then don’t give anything back in return.”