More than 700 Birmingham City Council back office staff have been told their jobs may disappear or be radically changed under the local authority's business transformation strategy.
A formal notice required under employment law warning of possible redundancies was issued in August. But the council did not specify at the time how many employees might be affected by the shake-up.
The scale of the changes being planned emerged at a meeting of the council audit committee. A spokesman later confirmed a Section 188 notice, giving notification of a "potential redundancy situation", applied to more than 700 staff in the corporate services department.
The administrative workers will all be affected by the corporate services transformation project which aims to transform IT services and cut costs by £800 million over ten years. Trade unions are nearing the end of a 90-day consultation period after which the new job descriptions and changed ways of working will be implemented.
Business transformation is intended to save £1.1 billion through cutting waste and making individual departments work together more efficiently. Council leaders remain adamant it is highly unlikely there will be any compulsory redundancies.
Chief executive Stephen Hughes blamed an "arcane law" for forcing the council to issue a formal redundancy warning. A Section 188 notice must be issued if an organisation intends to change the employment contracts of more than 20 workers.
Rumours that as many as 1,000 jobs might go were described as "completely fictitious" by Mr Hughes.
The audit committee was told consultation with the trade unions would continue in an attempt to seek a solution that would "minimise the impact on staff arising from uncertainty" and to avoid the council failing to realise the full benefits of corporate services transformation.
Alan Rudge, the cabinet member for human resources and equalities, said there was a "theoretical possibility" of redundancies but that would only happen if employees rejected all of the alternative jobs offered to them.
Coun Rudge (Con Sutton Vesey) said: "I find it irritating that you have to issue a notice because it makes it look as if you are making people redundant. If you are restructuring in any way, with a major change of terms and conditions, you have to serve a Section 188 notice."
He added: "If their job is changing through business transformation they may be offered a different job. It doesn't mean we are getting rid of them. It means there is the potential that you will no longer have the job you have at the moment.
"It is not our intention at this moment in time to make anyone redundant.
"What will happen is that most will be offered a job that is slightly different and most will accept. A small number of people may have to be relocated to look for alternative jobs within the city council.
"The vast majority will take similar jobs to what they have now which are well within their skill capacity."
Audit committee member Carl Rice claimed staff were fearful for their future.
Coun Rice (Lab Ladywood) said business transformation and the pay and grading review, which has seen more than 5,000 council employees suffer a pay cut, meant morale among the workforce was at an all-time low.
He added: "An atmosphere of uncertainty and fear is spreading quickly, and that is not conducive to the delivery of effective public services.
"Putting people into work that they are not trained for and not suitable for will be a recipe for disaster."