Union leaders say they have not ruled out industrial action in response to job cuts at Derby City Council.
The council has unveiled a plan aimed at helping it save £32m by 2012.
It includes 750 voluntary redundancies and changes to staff terms and conditions but could also see hundreds of compulsory redundancies.
Unison has held its first full meeting to discuss the situation and leaders said the council had to confirm how many jobs would be saved by any deal.
The savings package includes cutting the working week by one hour to 36 hours, reducing sick pay and charging for staff car parking.
Council officials have said that if fewer changes were accepted, more posts would be lost.
Unison regional organiser Charlie Carruth said: "We asked [the council], 'If we accept these cuts to terms and conditions, would you guarantee no compulsory redundancies?' and of course the answer was no.
"What we are saying is, 'If you tell us that if you are going to save £1m by doing X, you tell us where those jobs are being saved'."
He added industrial action was still an option: "We will gauge what the members want to do. We don't rule anything out but it is up to the members."
The council has said it is determined to keep redundancies to a minimum and it would launch a full consultation in the new year.