UP to 600 jobs with Sheffield Council could be affected as the authority struggles to make savings of at least £50m in future, it has warned.
Those savings will be on top of the £130m which has been cut over the last two years.
Full details of the job losses will not be clarified until the new year but it is expected that voluntary redundancy and early retirements will be used to help minimise the impact on workers, with some positions also going unfilled when staff leave.
Staff are also being asked to suggest their own ideas for saving money, such as reduced working hours and career breaks.
The local authority is now informing the Government of the number of jobs that might be affected.
It has to submit a HR1 form to the Department for Business, Innovation and Skills now to enable any consultations to take place next year with staff and trade unions over any potential redundancies from April 2013.
Trade union leaders have been informed of the forecasted figure.