Hundreds of council staff will see their wages reduced under the deal
Union leaders have said more than 600 council workers in south west Scotland have appealed against new pay levels.
Thousands of staff with Dumfries and Galloway Council received a pay rise on Monday worth about £9m-a-year in total.
However, more than 2,000 employees of the local authority saw their wages stay unchanged or will see their earnings cut in future.
A deadline for appeals was set for 16 February but that will be extended for staff whose managers are on holiday.
The process is part of the council's "single status" agreement to address historic pay inequalities.
More than 4,000 staff saw their wages rise on Monday and will receive nearly a year's back-pay next month.
However, the remainder of the council's 6,500 employees will get no increase or see their wages reduced after three years at their current level.
Unison branch secretary Marion Stewart said there were still ongoing negotiations with the council as hundreds of workers were unhappy.
"We are looking at probably about 10% of the work force which would be about 650," she said.
"It could be more than that.
"There are still some hiccups, particularly over terms and conditions that we're still negotiating with the council on."
She said those "discrepancies" needed to be sorted out quickly.
"It was not until people got their pay slips that these anomalies were identified," she said.