In a statement, the council’s director of communications and corporate governance Colin Edgar claimed Unison had betrayed its own members by not balloting them.
He said talks breaking down meant there was now “no agreed way forward between the council and the joint trade unions”.
“The council has gone as far as it can,” said Edgar. “The new pay and grading scheme removes unequal pay and sees pay rise or stay the same for 90% of staff – the council’s total pay bill will be substantially higher.
“For those staff who are in detriment our joint trade unions negotiated an increase in pay protection from six months to 12 months.
“Additionally, some trade unions are devoting energy to local consultations to mitigate the impact on those colleagues in detriment – focussing on providing specific solutions.”
Edgar said council officials hoped to meet with Unison earlier but the union had not attended the meeting.
He added: “The offer which has been unilaterally rejected by Unison would have taken dismissals off the table and seen additional cash for those members of staff, and members of all unions, who are due back pay.
“It beggars belief that they would betray their own members in this way.”
Unison has been contacted for comment.