Unions are considering legal action against the local authority
Unions are considering legal action in a dispute over back-pay details in a deal to address wage inequalities on Dumfries and Galloway Council.
The "single status" agreement came into force earlier this year with many staff receiving salary increases.
However, unions claim some employees are missing out on back-pay for overtime and additional hours worked.
The authority said it had "agreed to disagree" with unions on some matters and would await legal advice.
Thousands of council staff in Dumfries and Galloway received back-pay worth several million pounds earlier this month.
However, there is now dispute over arrears that might be due for any hours worked outside those contractually agreed.
The Joint Trade Unions (JTU), consisting of Unison and the GMB, have accused the council of "back tracking" on parts of the deal.
A statement said the council was "turning its back on a significant number of its own staff".
Unions said the authority had shown a "lack of forward planning, lack of co-ordination and lack of communication".
"The JTU are bitterly disappointed at this turn of events," said a statement.
It claimed the council was set to renege on the pay deal "purely as a cost-cutting exercise".
The statement added: "Not only is this unfair to staff who were told they would be paid for the work done but also the JTU indicated that this was a breach of the agreement and legal action is now being considered as an option to remedy this injustice."
A council spokesman said work to get the single status agreement fully in place was continuing.
However, he said the authority and the JTU differed in their understanding of the agreement on shift allowances and backdated travel time, additional hours and overtime payments.
"Legal advice is already being sought on the two different interpretations of the agreement by the unions and the council," he said.
"The issues will move forward once those recommendations are received."